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Rheological and Interfacial Properties of Colloidal Electrolytes
Hong-Peng Han, Yi-Hu Song, Qiang Zheng
Corrected proof , doi: 10.1007/s10118-019-2334-9
[Abstract](60) [FullText HTML](9) [PDF 844KB](7)
Electric conductivity and rheological responses of colloidal electrolytes consisting of lithium bis(trifluoromethanesulfon) imide, polyethylene glycol (PEG) oligomer, and fumed silica have been investigated. Incorporating silica could improve ionic conductivity of the electrolytes at the same lithium/oxygen ratios. The colloidal electrolytes demonstrate a sol to gel transition with increasing silica content while they exhibit shear thickening behaviors during steady flow at intermediate range of strain rate. The presence of lithium salt, on the one hand, could lower the crystallinity of PEG or forbid the crystallization and on the other hand, interferes the chain adsorption on the surface of silica. Furthermore, lithium salt strongly retards the segmental relaxation of PEG in the colloidal electrolytes.
Differential Polymorphic Transformation Behavior of Polybutene-1 with Multiple Isotactic Sequences
Ya-Ping Ma, Wei-Ping Zheng, Chen-Guang Liu, Hua-Feng Shao, Hua-Rong Nie, Ai-Hua He
In press , doi: 10.1007/s10118-020-2337-6
[Abstract](56) [PDF 498KB](10)
For the solid-solid transformation from form II to form I of isotactic polybutene-1 (iPB), the temperature dependence of form I nucleation and growth was deemed to control the transformation process. However, the relationship between form I formation and form II disappearance in the transformation process is not clear. In this work, the spontaneous crystal transformation from form II to I of iPB with 81 mol% mmmm sequence concentration is studied firstly by tracking the two processes, the decay of form II and the yielding of form I in a wide range of temperature spanning from 0 °C to 50 °C and in a long transformation time ranging from 5 min to 65 days with in situ FTIR and WAXD. Unlike the literature reports, the decay rate of form II is firstly found to be lower than the yielding rate of form I at all studied temperatures, especially at low transition temperature. This is attributed to the amorphous chains which locate near crystal lamella participating into the nucleation of form II. The regular chain folding and growth of iPB form I from amorphous chains containing short isotactic sequences also lead to an increase in crystallinity of form I compared with that of initial form II crystallized at 60 °C. An increase in the annealing temperature results in decrease in crystallinity and increase in lamellae thickness of iPB form I.
Deactivation Effect Caused by Catalyst-Cocatalyst Pre-contact in Propylene Polymerization with MgCl2-supported Ziegler-Natta Catalyst
Zhen Zhang, Bai-Yu Jiang, Biao Zhang, Zhi-Sheng Fu, Zhi-Qiang Fan
$v.latestStateEn , doi: 10.1007/s10118-019-2319-8
[Abstract](121) [FullText HTML](7) [PDF 653KB](1)
Propylene slurry polymerization with a MgCl2-supported Ziegler-Natta catalyst containing internal electron donor was conducted after different durations of pre-contact of the catalyst with triethylaluminum cocatalyst. The number of active centers ([C*]/[Ti]) was determined by quenching the polymerization with 2-thiophenecarbonyl chloride and measuring sulfur content in the polymer. The pre-contact treatment caused selective deactivation of a part of active centers with low stereoselectivity and much lower activity in the initial stage of polymerization as compared with the polymerization run without the pre-contact stage. The active center concentration and polymerization activity decreased with prolonging of the pre-contact stage. The proportion of stereoselective active centers was increased by prolonging the pre-contact stage, so the isotacticity of produced polypropylene was enhanced. Release of active centers through catalyst particle fragmentation was significantly retarded, and the polymerization rate curve changed from decay type to induction type by the pre-contact treatment. In the induction period both non-stereoselective and stereoselective active centers were released and activated, resulting in gradual reduction of the polymer’s isotacticity in the first 5−10 min of polymerization. Selective deactivation of non-stereoselective active centers also took place in propylene polymerization using the catalyst without pre-contacting with the cocatalyst. In this case, the polymerization rate decayed with time after a short induction period of 2−5 min. Over reduction of the active center precursors with low stereoselectivity by triethylaluminum was considered as the reason for their deactivation during the pre-contact or the polymerization processes.
pH-responsive AIE-active Polyethylene-based Block Copolymers
Yu Jiang, Nikos Hadjichristidis
Corrected proof , doi: 10.1007/s10118-019-2330-0
[Abstract](181) [FullText HTML](62) [PDF 698KB](20)
A novel synthetic strategy towards pH-responsive aggregation-induced emission (AIE)-active tetraphenylethene (TPE)-functionalized polyethylene-based block copolymers is presented. Tris(3-(4-(1,2,2-triphenylvinyl)phenoxy)propyl)borane was used to initiate the polyhomologation of dimethylsulfoxonium methylide to afford well-defined α-TPE-ω-OH linear polyethylenes (PE). The terminal hydroxyl groups were transformed to atom transfer radical polymerization (ATRP) initiating sites by esterification with α-bromoisobutyryl bromide, followed by polymerization of tert-butyl acrylate (tBA) to provide TPE-PE-b-PtBA block copolymers. After hydrolysis of the tBu group to COOH group, the corresponding pH-responsive TPE-PE-b-PAA block copolymers were obtained. All synthesized block copolymers revealed AIE behavior either in solution or bulk. Due to the pH-responsivity of PAA chains, the aggregation state at different pH and consequently the fluorescence intensity changed. Also, the synthesized block copolymers exhibited ion-specificity fluorescence properties.
Functionalized Copolymers of Isobutylene with Vinyl Phenol: Synthesis, Characterization, and Property
Shi-Xuan Yang, Zi-Yu Fan, Feng-Yu Zhang, Si-Hao Li, Yi-Xian Wu
Corrected proof , doi: 10.1007/s10118-019-2329-6
[Abstract](160) [FullText HTML](80) [PDF 2205KB](17)
The random copolymers of isobutylene (IB) with polar comonomers of 4-acetoxystyrene (ACS) or 4-tert-butoxystyrene (TBO), P(IB-co-ACS) and P(IB-co-TBO), could be successfully synthesized via cationic copolymerization with FeCl3-based initiating system. The kinetics of the cationic copolymerization process was in situ investigated by inserting a diamond probe into the reaction system by ATR-FTIR spectroscopy. The chemical structure and incorporation content of polar comonomers in the copolymers were characterized by GPC with RI/UV dual detectors and 1H-NMR spectroscopy. The corresponding functionalized random copolymers of IB with vinyl phenol P(IB-co-POH) carrying phenolic hydroxyl side groups could be further prepared via the complete hydrolysis of acetoxyl side groups in P(IB-co-ACS) or tert-butoxyl side groups in P(IB-co-TBO) copolymers. The functionalized P(IB-co-POH) copolymers became hydrophilic with water contact angle (WCA) of ca. 80° for the self-assembly in hot water, compared to the hydrophobic polyisobutylene with WCA of ca. 110°. The functionalized P(IB-co-POH) copolymers also displayed an excellent self-healing property due to the interaction of intermolecular hydrogen bonding and formation of three dimentional supramolecular networks from phenolic hydroxyl side groups. Furthermore, P(IB-co-POH) copolymers also provided a good matrix for the homogeneous dispersion for silica nanoparticles due to the formation of hydrogen bonding between copolymer chains and silica nanoparticles.
Synthesis and Properties of Hydroxytelechelic Polyisobutylenes by End Capping with tert-Butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane
Jing Li, Kang-Da Wu, Huang Shan, Jing-Han Zhang, Ming Zhao, Guang-Bi Gong, Wen-Li Guo, Yi-Bo Wu
Corrected proof , doi: 10.1007/s10118-019-2327-8
[Abstract](137) [FullText HTML](52) [PDF 715KB](7)
The low-activity cationic monomer tert-butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane was synthesized by Grignard reaction and hydroxyl-protection reaction. Living polyisobutylene chains were initially synthesized by controlled cationic polymerization and then capped with tert-butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane. The hydrolysis of these polyisobutylenes end capped with tert-butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane gave rise to hydroxytelechelic polyisobutylene. NMR analysis confirmed that the hydrolysis was complete. Results also showed that a low polymerization temperature favored the participation of tert-butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane in the end-capping reaction. Moreover, polyisobutylene-based polyurethane exhibited greater acid resistance than commercial polyurethane.
Rhodamine Mechanophore Functionalized Mechanochromic Double Network Hydrogels with High Sensitivity to Stress
Li-Jun Wang, Kai-Xiang Yang, Qiang Zhou, Hai-Yang Yang, Jia-Qing He, Xing-Yuan Zhang
Corrected proof , doi: 10.1007/s10118-019-2293-1
[Abstract](239) [FullText HTML](54) [PDF 640KB](17)
Mechanochromic hydrogels, a new class of stimuli-responsive soft materials, have potential applications in a number of fields such as damage reporting and stress/strain sensing. We prepared a novel mechanochromic hydrogel using a strategy that has been developed to prepare dual-network (DN) hydrogels. A hydrophobic rhodamine derivative (Rh mechanophore) was covalently incorporated into a first network as a cross-linker. This first network embedded with Rh mechanophore within the DN hydrogel was pre-stretched. This guaranteed that the stress could be transferred extensively to the Rh-crosslinked first network once the hydrogel was under an applied force. Interestingly, we found that the threshold stress required to activate the mechanochromism of the hydrogel was less than 200 kPa, and much less than those in previous reports. Moreover, because of the excellent sensitivity of the hydrogel to stress, the DN hydrogel exhibited reversible freezing-induced mechanochromism. Benefiting from the sensitivity of Rh mechanophore to both pH and force, the DN hydrogel showed pH-regulated mechanochromic behavior. Our experimental results indicate that the preparation strategy we used introduces sensitive mechanochromism into the hydrogel and preserves the advantageous mechanical properties of the DN hydrogel. These results will be beneficial to the design and preparation of mechanochromic hydrogels with high stress sensitivity, and foster their practical applications in a number of fields such as damage reporting and stress/strain sensing.
Polypropylene Separators with Robust Mussel-inspired Coatings for High Lithium-ion Battery Performances
Chao Zhang, Hong-Qing Liang, Jun-Ke Pi, Guang-Peng Wu, Zhi-Kang Xu
Corrected proof , doi: 10.1007/s10118-019-2310-4
[Abstract](150) [FullText HTML](97) [PDF 695KB](13)
The performances of lithium-ion batteries (LIBs) are dependent on the wettability and stability of porous separators. Mussel-inspired coatings seem to be useful to improve the surface wettability of commercialized polyolefin separators. However, it is still a challenge to guarantee their stability under polar electrolytes. Herein, we report a facile and versatile way to enhance the wettability and stability of polypropylene separators by constructing robust polydopamine (PDA) coatings triggered with CuSO4/H2O2. These coatings were conveniently deposited on the polypropylene separator surfaces and the PDA-coated separators exhibited the improved surface wettability and thermal stability. The electrolyte uptake increased nearly two folds from the pristine separator to the modified ones. Correspondingly, the ionic conductivity also rose from 0.82 mS·cm–1 to 1.30 mS·cm–1. Most importantly, the CuSO4/H2O2-triggered PDA coatings were very stable under strong polar electrolytes, endowing the cells with excellent cycle performance and enhanced C-rate capacity. Overall, the results unequivocally demonstrate that application of PDA coatings on polyolefin separator triggered by CuSO4/H2O2 is a facile and efficient method for improving the wettability and stability of separators for high LIBs performance.
Phase Behaviors of Soft-core Particle Systems
Ning Xu
Corrected proof , doi: 10.1007/s10118-019-2304-2
[Abstract](224) [FullText HTML](131) [PDF 4151KB](17)
This paper reviews some of our recent works on phase behaviors of particulate systems with a soft-core interaction potential. The potential is purely repulsive and bounded, i.e., it is finite even when two particles completely overlap. The one-sided linear spring (harmonic) potential is one of the representatives. This model system has been successively employed to study the jamming transition, i.e., the formation of rigid and disordered packings of hard particles, and establish the jamming physics. This is actually based on the " hard” aspect of the potential, because at low densities and when particle overlap is tiny the potential resembles the hard sphere limit. At high densities, the potential exhibits its " soft” aspect: with the increase of density, there are successive reentrant crystallizations with many types of solid phases. Taking advantage of the dual nature of the potential, we investigate the criticality of the jamming transition from different perspectives, extend the jamming scenario to high densities, reveal the novel density evolution of two-dimensional melting, and find unexpected formation of quasicrystals. It is surprising that such a simple potential can exhibit so rich and unexpected phenomena in phase transitions. The phase behaviors discussed in this paper are also highly regarded in polymer science, which may thus shed light on our understanding of polymeric systems or inspire new ideas in studies of polymers.
Non-fullerene Acceptors with a Thieno[3,4-c]pyrrole-4,6-dione (TPD) Core for Efficient Organic Solar Cells
Shi-Zhe Geng, Wei-Tao Yang, Jian Gao, Shui-Xing Li, Min-Min Shi, Tsz-Ki Lau, Xin-Hui Lu, Chang-Zhi Li, Hong-Zheng Chen
Corrected proof , doi: 10.1007/s10118-019-2309-x
[Abstract](189) [FullText HTML](99) [PDF 805KB](25)
To achieve the red-shifted absorptions and appropriate energy levels of A-D-A type non-fullerene acceptors (NFAs), in this work, we design and synthesize two new NFAs, named TPDCIC and TPDCNC, whose electron-donating (D) unit is constructed by a thieno[3,4-c]pyrrole-4,6-dione (TPD) core attached to two cyclopentadithiophene (CPDT) moieties at both sides, and the electron-accepting (A) end-groups are 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IC) and 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile (NC), respectively. Benefiting from TPD core, which easily forms quinoid structure and O···H or O···S intramolecular noncovalent interactions, TPDCIC and TPDCNC show more delocalization of π-electrons and perfect planar molecular geometries, giving the absorption ranges extended to 822 and 852 nm, respectively. Furthermore, the highest occupied molecular orbital (HOMO) levels of TPDCIC and TPDCNC remain relatively low-lying due to the electronegativity of the carbonyl groups on TPD core. Considering that the absorptions and energy levels of the two NFAs match well with those of a widely used polymer donor, PBDB-T, we fabricate two kinds of organic solar cells (OSCs) based on the PBDB-T:TPDCIC and PBDB-T:TPDCNC blended films, respectively. Through a series of optimizations, the TPDCIC-based devices yield an impressing power conversion efficiency (PCE) of 10.12% with a large short-circuit current density (JSC) of 18.16 mA·cm−2, and the TPDCNC-based ones exhibit a comparable PCE of 9.80% with a JSC of 17.40 mA·cm−2. Our work is the first report of the TPD-core-based A-D-A type NFAs, providing a good reference for the molecular design of high-performance NFAs.
Monomer-activated Copolymerization of Ethylene Oxide and Epichlorohydrin: In Situ Kinetics Evidences Tapered Block Copolymer Formation
Ann-Kathrin Danner, Daniel Leibig, Lea-Marie Vogt, Holger Frey
Corrected proof , doi: 10.1007/s10118-019-2296-y
[Abstract](193) [FullText HTML](91) [PDF 1020KB](4)
The monomer-activated anionic ring-opening copolymerization (AROP) of ethylene oxide (EO) and epichlorohydrin (ECH) using tetraoctylammonium bromide as an initiator and triisobutylaluminum (i-Bu3Al) as an activator was studied. The properties of the copolymers as well as the microstructure have been analyzed in detail via an in situ NMR kinetics study. The statistical copolymers exhibited molecular weights ranging from 2350 g·mol–1 to 38000 g·mol–1 (measured by SEC, PEG-standards) and moderate dispersities of 1.27–1.44. The thermal property tests revealed both a glass transition and melting for all copolymers, supporting a block-like nature. Applying in situ NMR kinetic measurements, the reactivity ratios of EO and ECH were determined to be strongly disparate, i.e., rEO = 9.2 and rECH = 0.10. This shows that the simple one-pot statistical anionic copolymerization of EO and ECH via the monomer-activated AROP resulted in the formation of strongly tapered, block-like structures. Furthermore, post-polymerization functionalization of the reactive chloromethyl groups by nucleophilic displacement was investigated for the copolymers. Copolymerization of EO and ECH offers a broad platform for further functionalization and therefore the possibility to prepare a variety of multifunctional PEGs.
Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VOx/SiO2 UHMWPE Catalysts
Yu-Long Jin, Lin Liu, Yu-Jie Wang, Zhen Liu, Bo-Ping Liu
Corrected proof , doi: 10.1007/s10118-019-2295-z
[Abstract](111) [FullText HTML](77) [PDF 0KB](1)
Recently, we reported the first VOx/SiO2 ethylene polymerization catalyst for making Cl-free UHMWPE, and found the dominant promotion effects of Al-/Ti-/Zr-modifications over this catalyst system (Macromol. Chem. Phys. 2017, 218, 1600443). In this work, density functional theory is applied to investigate the underlying mechanism of this remarkable promotion effect of Al-/Ti-/Zr-modifications on a molecular and atomic level. The cluster model with V(III) is found to be the most possible active site due to its lowest overall energy barrier for monomer insertion, though the process of C2H4 coordination and the subsequent formation of transition state are most energy favored for V(II) species. By modifying one of or both V―O―Si in the active model with V―O―M (M = Al, Ti, or Zr), the energy barrier for the binding of the upcoming C2H4 gets lower (particularly for Al- and Zr-modified catalysts), and the transition state also becomes more stable. Generally, the insertion process of C2H4 gets easier after support Al-/Ti-/Zr-modifications. This dominant promotion effect is partially ascribed to the more enriched positive charge distribution on or nearby the V center, and the narrower energy gap between the LUMO of model catalysts and the HOMO of C2H4 for these modified catalysts also contributes much. In addition, the decreased steric hindrance around the V center should be taken into account for the modified models as well. Furthermore, the Brønsted acidity of the catalysts is investigated by introducing a pendent hydroxyl group to the model catalysts, which has a close contact with the V center. Similar promotion effect of support modification by Al, Ti, and Zr could still be observed.
Recent Progress on COS-derived Polymers
Cheng-Jian Zhang, Xing-Hong Zhang
Corrected proof , doi: 10.1007/s10118-019-2288-y
[Abstract](249) [FullText HTML](65) [PDF 748KB](17)
The synthesis of sulfur-containing polymer, a very promising functional material, has made a great progress in the past several years. This review is focused on the very recent advances in poly(monothiocarbonate)s derived from carbonyl sulfide (COS) and epoxides including biomass-derived epoxides. Of significance, metal-free catalyst systems, including triethyl borane/Lewis base pair and thiourea/Lewis base pair are developed for the alternating copolymerization of COS with epoxides. Thereof, the thiourea/Lewis base pair is highly active to the copolymerization of COS with epoxide in a living manner. Moreover, a series of crystalline poly(monothiocarbonate)s are presented, including the copolymers derived from COS with oxetane, ethylene oxide, enantiopure epichlorohydrin, and achiral meso-epoxides via enantioselective copolymerization. Based on these COS/epoxide copolymerization process, a variety of COS-based block copolymers with well-defined structure are presented.
Readily Prepared and Tunable Ionic Organocatalysts for Ring-opening Polymerization of Lactones
Zhuo-Lun Jiang, Jun-Peng Zhao, Guang-Zhao Zhang
Corrected proof , doi: 10.1007/s10118-019-2285-1
[Abstract](168) [FullText HTML](99) [PDF 0KB](11)
Highly potent ionic organocatalyst is developed for room-temperature controlled ring-opening polymerization (ROP) of lactones, including δ-valerolactone, ε-caprolactone, and δ-hexalactone. The catalysts are prepared by simply mixing tetra-n-butyl ammonium hydroxide and a (thio)urea at elevated temperature under vacuum, and used in cooperation with an alcoholic initiator. The performance of the catalyst is readily adjusted and optimized through variation of the (thio)urea precursor, catalyst composition, and reaction condition. Urea-derived catalysts are generally superior to thiourea-derived ones. Provided with proper N-substituents, the catalyst affords both high polymerization efficiency and high selectivity for monomer enchainment over macromolecular transesterification, even at high monomer conversion and/or substantially extended reaction time. In addition to acidity, structural symmetry of the urea also proves decisive for the catalytic activity, which enables a catalyst-assisted proton transfer process for the ring-opening of lactone and thus provides a novel mechanistic insight for ROP catalyzed by hydrogen-bonding type bifunctional ionic organocatalysts.
Investigation on Viscoelasticity of Waterborne Polyurethane with Azobenzene-containing Pendant Groups under Ultraviolet and Visible-light Irradiation
Yi-Jun Liu, Dong Liu, Si-Han Li, Hua-Qing Liang, Fang-Ming Zhu
Corrected proof , doi: 10.1007/s10118-019-2289-x
[Abstract](222) [FullText HTML](73) [PDF 798KB](17)
In this study, a novel waterborne polyurethane (WPU) with azobenzene-containing (azo-containing) pendant groups was synthesized by isophorone diisocyanate, long-chain diol of polycaprolactone, 2-ethyl-2-methyl-butanoic acid (2,2-dimethylolpropionic acid), 10-(4-(phenyldiazenyl)phenoxy)decyl-3-hydroxy-2-(hydroxymethyl)-2-methylpropanoate, and N,N-diethyl-ethanamine (triethylamine). Moreover, the influence of ultraviolet and visible (UV-Vis) light irradiation on the viscoelasticity of azo-containing WPU film in terms of the reversible trans-cis photoisomerization of azo-containing pendant groups was investigated by UV-Vis light spectroscopy, atomic force microscopy, and dynamic thermomechanical analysis. The results revealed that the adhesion of azo-containing WPU with single crystal silicon atomic force microscope probe was about 13 nN when irradiated by 450 nm Vis light for 60 s at 25 °C. Subsequently, the adhesion increased to 82 nN after irradiation with 365 nm UV light for 60 s at 25 °C. In addition, the azo-containing WPU presented a photo-induced reversible transition of tensile modulus and tanδ in the range from about 2 MPa to 22 MPa and 6000 to 0.35 with UV-Vis light cyclic irradiation for 120 s at 25 °C, respectively.
A Well-defined Hierarchical Hydrogen Bonding Strategy to Polyureas with Simultaneously Improved Strength and Toughness
Ting Li, Tian-Ze Zheng, Zhao-Xia Guo, Jun Xu, Bao-Hua Guo
Corrected proof , doi: 10.1007/s10118-019-2275-3
[Abstract](171) [FullText HTML](67) [PDF 1016KB](12)
A well-defined quadruple hydrogen bonding strategy involving dimerization of 2-ureido-4[1H]-pyrimidone (UPy) units is innovatively designed to prepare polyureas with high overall mechanical properties. Three polyureas containing different amounts of UPy units were synthesized by replacing a portion of isophorone diisocyanate (IPDI) with a UPy-derived diisocyanate. The formation of quadruple hydrogen bonds in hard segments via UPy dimers was confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties of the polyureas were evaluated by uniaxial tensile testing. Compared to the polyurea without UPy units, remarkable improvements in Young’s modulus, tensile strength, and toughness were simultaneously achieved when UPy units were incorporated. The mechanism behind the strong strengthening effect rooted in the stronger intermolecular forces among hard segments brought by the quadruple hydrogen bonds, which were stronger than the inherent bidentate and monodentate hydrogen bonds among urea groups, and the slower soft segmental dynamics reaveled by both increased Tg and relaxation time of the soft segments. The mechanism behind the strong toughening effect was ascribed to more effective energy dissipation brought by the quadruple hydrogen bonds that served as stronger sacrificial bonds upon deformation. This work may offer new insight into the design of polyurea elastomers with comprehensively improved mechanical properties.
Biofilm Disruption Utilizing α/β Chimeric Polypeptide Molecular Brushes
Si Zhang, Xi-Mian Xiao, Fan Qi, Peng-Cheng Ma, Wei-Wei Zhang, Cheng-Zhi Dai, Dan-Feng Zhang, Run-Hui Liu
Corrected proof , doi: 10.1007/s10118-019-2278-0
[Abstract](123) [FullText HTML](86) [PDF 0KB](3)
Gram-negative bacteria can cause serious infections and are well known problems in biomedical practices. Biofilms of gram-negative bacteria are notorious for their frequently encountered resistance toward antibiotics. We demonstrate that α/β chimeric polypeptide molecular brush (α/β CPMB) exerts potent activities against antibiotic-resistant gram-negative bacteria. MTT viability assay, bacterial colony counting, and live/dead staining all indicate that α/β CPMB not only inhibits biofilm formation of gram-negative Pseudomonas aeruginosa and Acinetobacter baumannii, but also effectively disrupts mature biofilms that are highly resistant to one of the most active antibiotics—colistin. The superior antibacterial performance of the α/β CPMB implies its potential topical applications in treating biofilms.
Computational Design and Fabrication of Enantioselective Recognition Sorbents for L-phenylalanine Benzyl Ester on Multiwalled Carbon Nanotubes Using Molecular Imprinting Technology
T Sajini, Renjith Thomas, Beena Mathew
Corrected proof , doi: 10.1007/s10118-019-2282-4
[Abstract](163) [FullText HTML](69) [PDF 1854KB](8)
Computational strategies have been employed to investigate the influence of the nature of monomers and cross-linker in order to design three dimensional imprinted polymers with selective recognition sites for L-phenylalanine benzyl ester (L-PABE) molecule. Here, computational chemistry methods were applied to screen the molar quantity of functional monomers that interact with one mole of the template molecule. Effects of the nature of functional monomer, cross-linker, and molar ratio were determined computationally using density functional calculations with B3LYP functional and generic 6-31G basis set. Methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) were used as the functional monomer and crosslinking agent, respectively. L-PABE imprinted polymer layered on multiwalled carbon nanotube (MWCNT) and conventional bulk MIP were synthesised and characterized as well. To investigate the influence of pre-organization of binding sites on the selectivity of L-PABE, respective non-imprinted polymers were also synthesised. MWCNT-MIPs and MIPs exhibited the highest adsorption capacity towards L-PABE. The synthesized polymers revealed characteristic adsorption features and selectivity towards L-PABE in comparison with those of its enantiomer analogues.
A Luminescent Thermometer Based on Linearly Thermo-responsive Copolymer and Polyoxometalates
Jin-Long Zhang, Jun-Yan Tan, Xin-Hua Wan, Jie Zhang
Corrected proof , doi: 10.1007/s10118-019-2287-z
[Abstract](179) [FullText HTML](72) [PDF 610KB](9)
A novel switchable luminescent thermometer based on thermo-responsive triblock copolymer poly(ethylene glycol)-b-poly(acrylamide-co-acrylonitrile-co-dimethylaminoethylmethacrylate) (PEO113-b-P(AAm264-co-AN112-co-DMA8)) and Eu-containing polyoxometalate (Eu-POM) was successfully constructed. The copolymer synthesized by RAFT exhibited a linear response to temperature variations in aqueous media, which was quite different from the uncharged copolymer P(AAm-co-AN) having a specific upper critical solution temperature (UCST). Eu-POM was surrounded around thermo-responsive blocks through electrostatic interactions, and its luminescence could be finely tuned due to the sensitivity of copolymer to the temperature variation. In cold water, POMs were trapped in highly hydrophobic cores, exhibiting an intense emission. With the upraising of temperature, the emission intensity presented a gradual decrease and showed a linear correlation with temperature. When the complex solution cooled down, the luminescence could also be perfectly restored. This temperature-luminescence correlation could be held for numerous trials, showing a potential application in thermometer.
Studies on Rheological, Thermal, and Mechanical Properties of Polylactide/Methyl Methacrylate-Butadiene-Styrene Copolymer/Poly(propylene carbonate) Polyurethane Ternary Blends
Ji-Li Zhao, Hong-Wei Pan, Hui-Li Yang, Jun-Jia Bian, Hui-Liang Zhang, Ge Gao, Li-Song Dong
Corrected proof , doi: 10.1007/s10118-019-2276-2
[Abstract](93) [FullText HTML](68) [PDF 0KB](1)
Polylactide (PLA), methyl methacrylate-butadiene-styrene copolymer (MBS), and poly(propylene carbonate) polyurethane (PPCU) were blended and subjected to blown film process. The rheological, mechanical, morphological, thermal, and crystalline properties of the PLA/MBS/PPCU ternary blends and the mechanical properties of the resulting films were studied. Results of mechanical test showed that PPCU and MBS could synergistically toughen PLA. The impact strength of 50/10/40 PLA/MBS/PPCU blend (74.7 kJ/m2) was about 7.5 times higher than that of the neat PLA (10.8 kJ/m2), and the elongation at break of 50/10/40 PLA/MBS/PPCU blend (276.5%) was higher by about 45 times that of PLA (6.2%). The tear strength of PLA/MBS/PPCU films was 20 kN/m higher than that of PLA, and the elongation at break (MD/TD) of 50/10/40 PLA/MBS/PPCU films was 271.1%/222.3%, whereas that of PLA was only 2.7%/3.0%. POM observations displayed that the density of spherulite nucleation increased and the size of crystalline particles decreased with the addition of MBS. With increasing PPCU content from 5% to 20%, the density of spherulite nucleation increased and the size of crystalline particles decreased continuously, but the nucleation density of spherulites was slightly lowered with increasing PPCU content from 30% to 40%. The PLA/MBS/PPCU films exhibited excellent mechanical properties, which expanded the application range of these biodegradable films.
Synthesis and Properties of Photodegradable Poly(furan-amine)s by a Catalyst-free Multicomponent Cyclopolymerization
Wei-Qiang Fu, Gui-Nan Zhu, Jian-Bing Shi, Bin Tong, Zheng-Xu Cai, Yu-Ping Dong
Corrected proof , doi: 10.1007/s10118-019-2281-5
[Abstract](201) [FullText HTML](76) [PDF 1266KB](22)
A series of new photodegradable poly(furan-amine)s (PFAs) were synthesized by a one-pot, catalyst-free, multicomponent cyclopolymerization between diisocyanides, dialkylacetylene dicarboxylates, and aromatic dialdehydes. All polymerizations were conducted in toluene at 100 °C for 6 h without inert gas protection and furnished polymers with a satisfactory molecular weight (Mw up to 32200) and yield. The PFA structure was confirmed by spectroscopic techniques, such as GPC, FTIR, and NMR, as well as by comparison with a model compound. The polymers exhibited good solubility in common organic solvents and thermal stability. All the PFAs had high refractive indices in the visible light region (400 nm to 800 nm). Moreover, the PFAs were substantially degraded by UV irradiation due to the presence of furan rings. The film thickness reduction rate could be over 90%.
Orientation Efforts as Regulatory Factor of Structure Formation in Permeable Porous Poly(vinylidene fluoride) Films
G. K. Elyashevich, I. S. Kuryndin, I. Yu. Dmitriev, V. K. Lavrentyev, N. N. Saprykina, V. Bukošek
Corrected proof , doi: 10.01007/s10118-019-2284-2
[Abstract](164) [FullText HTML](66) [PDF 770KB](6)
The manufacturing process of poly(vinylidene fluoride) microporous films containing through flow channels and permeable to liquids has been elaborated. The process is based on polymer melt extrusion with subsequent stages of annealing, uniaxial extensions (" cold” and " hot” drawing), and thermal stabilization. The effect of orientation parameters (melt draw ratio and extension degrees) on overall porosity, permeability, morphology, and content of polar piezoactive β-phase in crystalline structure of the films was investigated by filtration porosimetry, sorptometry, scanning electron microscopy, X-ray scattering, and mechanical properties measurements. It is shown that the through pores were formed by a percolation mechanism. It is observed that permeability and the β-phase content increased with the growth of extension degree at the pore formation stages but the portion of β-crystallites decreased with increasing melt draw ratio at extrusion, which permitted to regulate the combination of through permeability and piezoactivity values by variation of the preparation process parameters.
Cationic Polymerization of Isobutylene and C4 Mixed Feed Using Complexes of Lewis Acids with Ethers: A Comparative Study
Dmitriy I. Shiman, Ivan A. Berezianko, Irina V. Vasilenko, Sergei V. Kostjuk
Corrected proof , doi: 10.1007/s10118-019-2290-4
[Abstract](156) [FullText HTML](62) [PDF 457KB](5)
The cationic polymerization of C4 mixed feed and isobutylene co-initiated by AlCl3×OiPr2, iBuAlCl2×nOiPr2, and [emim]Cl-FeCl3×nOiPr2 ([emim]Cl: 1-ethyl-3-methylimidazolium chloride) has been investigated. AlCl3×OiPr2 co-initiated cationic polymerization of C4 mixed feed proceeds at a lower rate than polymerization of isobutylene affording polymers with higher molecular weight. Complexes of iBuAlCl2 with diisopropyl ether of different compositions are more suitable co-initiators than AlCl3×OiPr2 for the synthesis of highly reactive polyisobutylene (HR PIB) from C4 mixed feed due to their higher activity in the polymerization as well as possibility to prepare polyisobutylenes with lower molecular weight and higher content of exo-olefin end groups. However, iBuAlCl2 needs activating via addition of external water (initiator) and/or interaction with salts hydrates in order to increase the reaction rate and the saturated monomer conversion. [Emim]Cl-FeCl3/iPr2O is a quite promising catalyst for the preparation of HR PIB with high exo-olefin end group content (> 80%) and relatively low polydispersity (Mw/Mn < 2.8) via cationic polymerization of C4 mixed feed. The sonication of reaction mixture in case of using [emim]Cl-FeCl3 allowed increasing the reaction rate and decreasing the molecular weight.
Polyether-polyester and HMDI Based Polyurethanes: Effect of PLLA Content on Structure and Property
Lei Shi, Ruo-Yu Zhang, Wu-Bin Ying, Han Hu, Yu-Bin Wang, Ya-Qian Guo, Wen-Qin Wang, Zhao-Bin Tang, Jin Zhu
Corrected proof , doi: 10.1007/s10118-019-2283-3
[Abstract](220) [FullText HTML](94) [PDF 1235KB](14)
Thermoplastic poly(ether-ester-urethane)s were synthesized from poly(L-lactide) diols (PLLA diols), polytetrahydrofuran diol (PTMG diols), 4,4′-dicyclohexylmethane diisocyanate (HMDI), and 1,4-butanediol (BDO) by a two-step reaction, and the morphology and property of the resultant TPU could be adjusted by varying the PLLA contents. The soft segment was composed of PLLA and PTMG diols. By controlling the percentage of PLLA in the soft segment, the glass transition temperature and mechanical properties of the polyurethanes could be regulated. Based on the FTIR spectrum, we found that two kinds of hydrogen bonding existed individually in soft matrix and hard domain. The hydrogen bonding in soft matrix was unstable, which could be destroyed during elongation. With in situ stretching WAXS and SAXS experiments, we found that the PLLA crystal was destroyed and the PLLA domain oriented along the stretch direction. Finally, we proposed a schematic model to illustrate the microstructures of these elastomers before and after stretch.
Synthesis of Polycarbonate Block Terpolymers Using Robust Cobalt Catalyst Systems
Ying-Jie Jiang, Wei-Min Ren, Ye Liu, Xiao-Bing Lu
Corrected proof , doi: 10.1007/s10118-019-2270-8
[Abstract](158) [FullText HTML](87) [PDF 730KB](4)
This contribution reports an efficient approach for preparing polycarbonate block terpolymers by immortal stepwise copolymerization of CO2 with different epoxides in the presence of enol chain transfer, mediated by robust cobalt catalyst systems consisting of the fluorine substituted salenCo(III)NO3 or biphenol-linker bimetallic Co(III) complex in conjunction with an ionic cocatalyst, PPNX (PPN = bis(triphenylphosphine)iminium, X = NO3 or 2,4-dinitrophenoxide). Various polycarbonate block terpolymers were obtained in perfectly unimodal distribution of their molecular weights with narrow polydispersity. They all possessed only one broad glass transition temperature, which could be adjusted by altering the length of different polycarbonate segments.
Preparation of Three Dimensional Hydroxyapatite Nanoparticles/Poly(vinylidene fluoride) Blend Membranes with Excellent Dye Removal Efficiency and Investigation of Adsorption Mechanism
Jian-Hua Li, Hui Zheng, Hua-Xiang Lin, Bo-Xin Zhang, Jia-Bin Wang, Tong-Lei Li, Qi-Qing Zhang
Corrected proof , doi: 10.1007/s10118-019-2271-7
[Abstract](172) [FullText HTML](103) [PDF 1643KB](4)
In this work, poly(vinylidene fluoride) (PVDF) membranes with hydrophilicity as well as preeminent mechanical strength and dye removal efficiency were fabricated by blending with three dimensional hydroxyapatite nanoparticles (HAPNPs). Surface chemical composition and morphology of the prepared membranes were systematically investigated by ATR-FTIR, XPS, XRD, FESEM, and EDS mapping analyses. The results verified that a large number of HAPNPs were successfully embedded on the modified membrane cross-sections. Moreover, HAPNPs content in the casting solution is an important factor that could have profound influence on the structures and performances of PVDF/HAPNPs blend membranes. The optimal membrane M2 with 2 wt% HAPNPs exhibited excellent hydrophilicity, outstanding mechanical strength of 19.60 MPa, and high water flux of (2466 ± 31) L·m–2·h–1. The maximum static adsorption capacity of the optimal membrane was about 10.83 mg/g, which is 3.75 times that of the pristine PVDF membrane (2.89 mg/g). PVDF/HAPNPs membranes were not only utilized for static adsorption, but also applied to dynamic dye removal. The possible adsorption mechanism between Congo red (CR) and HAPNPs embedded on the blend membranes was firstly discussed in this work. HAPNPs interacted with CR via Lewis reaction, hydrogen bond interaction, as well as electrostatic attraction to achieve the adsorption effect. Herein, the PVDF/HAPNPs blend membranes with extraordinary hydrophilicity, mechanical strength, and dye removal efficiency possess tremendous potential for practical applications of wastewater treatment.
Effects of Main-chain and Chain-ends on the Organogelation of Stearoyl Appended Pendant Valine Based Polymers
Mridula Nandi, Swagata Pan, Dipannita Ghosh, Priyadarsi De
Corrected proof , doi: 10.1007/s10118-019-2265-5
[Abstract](211) [FullText HTML](101) [PDF 908KB](8)
In this work, we investigated the effect of hydrophobic interactions between the polymeric backbone and chain-end groups on the self-assembly pathway of stearoyl appended side-chain valine (Val)-based poly(methacrylate/acrylate) homopolymers in different organic hydrocarbons. Gelation studies conducted revealed that while polymers with polyacrylate as backbone induces gelation in several organic hydrocarbons, polymers with polymethacrylate in the main-chain significantly hinders macroscopic gelation. Morphology of the organogels was analysed by field emission scanning electron microscopy (FESEM), and mechanical strengths of the organogels were determined by rheological measurements. Reversible addition-fragmentation chain transfer (RAFT) polymerization chain transfer agents (CTA)s, [R1―S―C=(S)―S―R2] with different ―R1 and ―R2 groups, have been employed to study the effect of structural variation at the chain-end on macroscopic assembly mechanism. We found that the additional interactions between terminal groups via hydrogen-bonding or π-π stacking interactions or both help to build up the self-assembly pathway and thereby produces mechanically stable organogels.
The Effect of Reaction Conditions on the Synthesis of Thermoplastic Elastomers Containing Polyalloocimene, Polyisobutylene and Tapered Blocks
Jozsef Kantor, Judit E Puskas, Gabor Kaszas
Corrected proof , doi: 10.1007/s10118-019-2254-8
[Abstract](217) [FullText HTML](144) [PDF 783KB](9)
This work investigates the effect of reaction conditions on the copolymerization of isobutylene (IB) with alloocimene (Allo) in methyl chloride (MeCl) using AlCl3 and ethylaluminum dichloride (EtAlCl2) as coinitiators and adventitious moisture as the initiator. Both AlCl3 and EtAlCl2 produced high molecular weight (Mn > 1.0 × 105 g/mol) thermoplastic elastomers (TPEs) with good mechanical properties in short reaction time (< 10 min). These unique TPEs have unsaturations in the end blocks, leading to easy functionalization and/or crosslinking.
Preparation and Characterization of Multi-layer Poly(arylene sulfide sulfone) Nanofibers Membranes for Liquid Filtration
Zhen-Yan Liu, Zhi-Mei Wei, Xiao-Jun Wang, Gang Zhang, Sheng-Ru Long, Jie Yang
Corrected proof , doi: 10.1007/s10118-019-2280-6
[Abstract](192) [FullText HTML](113) [PDF 3759KB](15)
Owing to the excellent filtration performance and low energy cost, polymeric nanofibers microfiltration (MF) membranes have attracted increasing attentions. Poly(arylene sulfide sulfone) (PASS), as one of the structurally modified polymers based on poly(phenylene sulfide) (PPS), has been selected as the raw material to fabricate nanofibers MF membranes via electrospun techniques. The effects of PASS solution and the electrospinning processing parameters on the structural morphology of nanofibers were investigated in detail. The average diameter of PASS nanofibers was (296 ± 46) nm under the optimal condition: polymer concentration of 0.27 g·mL–1 PASS/DMI, applied voltage of 20 kV, and speed of collector drum of 300 r·min–1. And then the multi-layer PASS nanofibers MF membranes were fabricated from cold-pressing the optimized PASS nanofibers (as-prepared PASS nanofibers) membrane. The morphology, porosity, pore size, mechanical properties, and surface wettability of the multi-layer PASS nanofibers MF membranes could be tuned by the layers of as-prepared nanofibers membrane. The results demonstrated that the membrane with 6 layers (marked as PASS-6) exhibited the smallest porosity, smallest pore size, highest mechanical property, and best surface wettability. Meanwhile, the multi-layer PASS nanofibers MF membranes showed that the rejection ratio gradually increased, while the pure water flux decreased with increasing membranes thickness. The PASS-6 membrane exhibited large water flux of 747.76 L·m–2·h–1 and high separation efficiency of 99.9% to 0.2 μm particles, making it a promising candidate for microfilter.
Mechanical Properties of Interlocked-ring Polymers: A Molecular Dynamics Simulation Study
Zheng-Tao Wu, Jia-Jia Zhou
Corrected proof , doi: 10.1007/s10118-019-2279-z
[Abstract](208) [FullText HTML](82) [PDF 767KB](15)
Interlocked-ring polymers, also known as polycatenanes, possess an interesting molecular architecture. These polymers are composed of many interlocked rings in a linear chain. The topological constrain between neighboring rings distinguishes the interlocked-ring polymer from its linear counterpart. Here we present extensive molecular dynamic simulations on the interlocked-ring polymers and analyze the static properties of the polymer. By applying external forces to the polymer, we also study the force-extension curves of the polymer, which provides rich information about the mechanical properties of the interlockedring polymers.
Dimethylacetamide-promoted Direct Arylation Polycondensation of 6,6′-Dibromo-7,7′-diazaisoindigo and (E)-1,2-bis(3,4-difluorothien-2-yl)ethene toward High Molecular Weight n-Type Conjugated Polymers
Kai Guo, Yu Jiang, Ying Sui, Yun-Feng Deng, Yan-Hou Geng
Corrected proof , doi: 10.1007/s10118-019-2277-1
[Abstract](196) [FullText HTML](81) [PDF 689KB](8)
A highly efficient and eco-friendly protocol for the synthesis of an alternating copolymer poly(7,7′-diazaisoindigo-alt-(E)-1,2-bis(3,4-difluorothien-2-yl)ethene) (PAIID-4FTVT) via direct arylation polycondensation (DArP) is presented. Through detailed study, we found that the inhibitory effect of 7,7′-diazaisoindigo on DArP stemmed from the coordination of N atom with catalyst can be overcome by using dimethylacetamide (DMAc) as the co-solvent. Thus, PAIID-4FTVT with number-average molecular weight (Mn) > 100 kDa was synthesized via DArP by optimizing the content of DMAc. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectroscopy revealed that PAIID-4FTVT was defect-free. Top gate and bottom contact (TG/BC) organic thin-film transistors (OTFTs) were fabricated to characterize the semiconducting properties of the polymers. PAIID-4FTVT displayed unipolar n-type characteristics with the electron mobility (μe) strongly dependent on Mn. The highest μe up to 0.25 cm2·V–1·s–1 was achieved with the high molecular weight sample.
Co-delivery of Doxorubicin and Afatinib with pH-responsive Polymeric Nanovesicle for Enhanced Lung Cancer Therapy
Heng-Ye Gong, Yan-Gui Chen, Xing-Su Yu, Hong Xiao, Jin-Peng Xiao, Yong Wang, Xin-Tao Shuai
Corrected proof , doi: 10.1007/s10118-019-2272-6
[Abstract](217) [FullText HTML](88) [PDF 839KB](15)
Drug-resistance and drastic side effects are two major issues of traditional chemotherapy which may result in trail failure even death. Nanoparticle-mediated multidrug combination treatment has been proven to be a feasible strategy to overcome these challenges. In the present study, amphipathic block polymer of methoxyl poly(ethylene glycol)-poly(aspartyl(dibutylethylenediamine)-co-phenylalanine) (mPEG-P(Asp(DBA)-co-Phe)) was synthesized and self-assembled into pH-responsive polymeric vesicle. The vesicle was utilized to co-deliver cancer-associated epidermal growth factor (EGFR) inhibitor of afatinib and DNA-damaging chemotherapeutic doxorubicin hydrochloride (DOX) for enhanced non-small-cell lung cancer (NSCLC) therapy. As evaluated in vitro, the pH-responsive design of nanovesicle resulted in a rapid release of encapsulated drugs into tumor cells and caused enhanced cell apoptosis. In addition, in vivo therapeutic studies were conducted and the results evidenced that the co-delevery of DOX and afatinib using pH-sensitive nanovector was a promising strategy for NSCLC treatment.
Inhomogeneous Natural Network Promoting Strain-induced Crystallization: A Mesoscale Model of Natural Rubber
Han Liu, Guang-Su Huang, Lai-Yun Wei, Jian Zeng, Xuan Fu, Cheng Huang, Jin-Rong Wu
Corrected proof , doi: 10.1007/s10118-019-2267-3
[Abstract](199) [FullText HTML](90) [PDF 1477KB](3)
Although synthetic rubbers show continuously improved mechanical properties, natural rubber (NR) remains irreplaceable in the rubber family due to its superior mechanical properties. A mainstream viewpoint regarding the superiority of NR is that NR possesses a natural network formed by linking the poly(cis-1,4-isoprene) chain terminals to protein and phospholipid aggregates; after vulcanization, the natural network additionally contributes to rubber mechanics by both increasing the network density and promoting the strain-induced crystallization (SIC) behavior. However, the reason why the natural network promotes SIC is still unclear; in particular, only using the increased network density cannot explain our finding that the NR shows smaller onset strain of SIC than Gel (the gel component of NR with higher network density) and even vulcanized NR. Herein, we point out that the inhomogeneous chain deformation is the alternative reason why SIC of NR takes place at smaller strain than that of Gel. More specifically, although the natural network is homogenous on the subchain length scale based on the proton double-quantum NMR results, it is essentially inhomogeneous on mesoscale (100 nm), as revealed by the small angle X-ray scattering analysis. This inhomogeneous network also leads to the mesoscale deformation inhomogeneity, as detected by the orientation of stearic acid (SA) probe, thus resulting in the smaller onset strain of SIC of NR. Based on the experimental results, a mesoscale model is proposed to qualitatively describe the crucial roles of inhomogeneous structure and deformation of natural network in NR’s mechanical properties, providing a clue from nature to guide the development of high-performance rubbers with controlled structures at mesoscale.
Synthesis and Properties of Reversible Disulfide Bond-based Self-healing Polyurethane with Triple Shape Memory Properties
Han Jia, Kun Chang, Shu-Ying Gu
In press , doi: 10.1007/s10118-019-2268-2
[Abstract](213) [FullText HTML](94) [PDF 1230KB](12)
A reversible disulfide bond-based self-healing polyurethane with triple shape memory properties was prepared by chain extending of random copolymer poly(lactide-co-caprolactone) (PCLA), hexamethylene diisocyanate (HDI), polytetrahydrofuran (PTMEG), and 4,4′-aminophenyl disulfide. The chemical structures were characterized using 1H nuclear magnetic resonance (1H-NMR) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). The thermal properties, self-healing properties, triple-shape memory effect, and quantitative shape memory response were evaluated by differential scanning calorimetry (DSC), tensile tests, two-step programming process thermal mechanical experiments, and subsequent progressive thermal recovery. The self-healing mechanism and procedures were investigated using polarizing optical microscopy (POM) and an optical profiler. It was concluded that self-healing properties (up to 60%) and triple-shape memory properties around 35 and 50 °C (with shape fixation ratios of 94.3% and 98.3%, shape recovery ratios of 76.6% and 85.1%, respectively) were integrated to the shape memory polyurethane. As-prepared polyurethane is expected to have potential applications in multi-shape coatings, films, and step-by-step deploying structures.
Miscibility and Crystallization Behavior of Novel Branched Poly(ethylene succinate)/Poly(vinyl phenol) Blends
Kang-Jing Zhang, Zhao-Bin Qiu
Corrected proof , doi: 10.1007/S10118-019-2269-1
[Abstract](225) [FullText HTML](92) [PDF 759KB](12)
The blends of novel branched poly(ethylene succinate) (b-PES) and poly(vinyl phenol) (PVPh) were prepared via a solution and casting method. The miscibility, melting behavior, spherulitic morphology and growth, and crystal structure of b-PES/PVPh blends were investigated in detail. PVPh was miscible with b-PES over the whole compositions as evidenced by the single composition dependent glass transition temperature. Double melting behavior occurred in neat b-PES and b-PES/PVPh 85/15 blend after isothermal melt crystallization, which may be explained by the melting, recrystallization, and remelting mechanism. In addition, the depression of equilibrium melting point of an 85/15 blend was also found, confirming again the miscibility between the two components. The addition of PVPh caused the decrease of nucleation density and crystal growth rates of b-PES spherulites in the blend. The crystal structure of b-PES was unchanged before and after blending; moreover, the crystallinity of b-PES decreased slightly in the blend.
Crystallization and Phase Behavior in Block Copolymer Solution: An in Situ Small Angle X-ray Scattering Study
Hong-Yan Zhu, Feng Tian, Xiu-Hong Li, Hui-Bin Qiu, Jie Wang
Corrected proof , doi: 10.1007/s10118-019-2258-4
[Abstract](251) [FullText HTML](153) [PDF 1101KB](31)
Amphiphilic diblock copolymers self-assemble into a variety of micellar structures with diverse shapes in selective solvents. Here, we study the concentration and temperature dependence of the packing structure of spherical micelles of a polyisoprene-b-poly(2-vinylpyridine) (PI-b-P2VP) diblock copolymer in toluene using synchrotron radiation small angle X-ray scattering (SR-SAXS) and atomic force microscopy (AFM) techniques. Randomly packed spherical micelles are detected in dilute solutions, while in concentrated solutions, face-centered cubic (FCC), body-centered cubic (BCC) mixed crystal structures, and pure BCC crystal structures are observed with an increase in concentration. In situ SAXS experiments on the FCC/BCC mixed crystal structures reveal a novel FCC/BCC → BCC → Disorder → BCC phase behavior during the thermal annealing process. These results demonstrated that the BCC phase is apparently more stable than the FCC phase in the current sphere-packing system and FCC/BCC is a metastable state. The incompatibility of the PI and P2VP blocks decreases at a higher temperature and renders the variation of domain spacing.
Cu(0) Wire-mediated Single-electron Transfer-living Radical Polymerization of Oligo(ethylene oxide) Methyl Ether Acrylate by Selecting the Optimal Reaction Conditions
Liang Ding, Juan Li, Rui-Yu Jiang, Ling-Fang Wang, Wei Song, Lei Zhu
Corrected proof , doi: 10.1007/s10118-019-2263-7
[Abstract](238) [FullText HTML](90) [PDF 1080KB](6)
The efficient Cu(0) wire-catalyzed single-electron transfer-living radical polymerization (SET-LRP) in organic solvents and mixtures of the organic solvents with water has been thoroughly investigated. Oligo(ethylene oxide) methyl ether acrylate was used as an exemplar oligomer monomer to determine the optimum polymerization conditions for rapid, controlled, and quantitative production of well-defined polymers. The effects of Cu(0)-wire length (12.5 or 4.5 cm), ligand type (tris(dimethylaminoethyl)amine, Me6-TREN, or tris(2-aminoethyl)amine, TREN), and solvent type (dipolar aprotic solvents, cyclic ethers, alcohol, or acetone) on the polymerization have been evaluated. Kinetic experiments were performed for all polymerizations to assess the " living” behavior of each system employed. Importantly, TREN could be used as a replacement for Me6-TREN in Cu(0) wire-catalyzed SET-LRP of oligomer monomer, which probably provides the most economical and efficient methodology since TREN is 80 times less expensive than Me6-TREN. The high chain-end fidelity of resulting polymer was experimentally verified by thiol-Michael addition reaction at the α-Br chain end and subsequent chain extension with methyl acrylate.
Amphiphilic Dendrimer-like Copolymers with High Chain Density by Living Anionic Polymerization
Ke Zheng, Jun-Po He
Corrected proof , doi: 10.1007/s10118-019-2247-7
[Abstract](355) [FullText HTML](153) [PDF 2749KB](18)
We report here a method for the preparation of amphiphilic dendrimer-like copolymers with dendritic polystyrene (PS) core and protonated poly(2-vinyl pyridine) (P2VP) or poly(methacrylic acid) (PMAA) shell. The method employed the efficient coupling reaction of anionic living polymer chains and chlorosilane. The synthesis started from a functionalized 3rd generation dendritic polystyrene, G3PS-g-SiCl, used as the precursor. The dendrimer-like copolymer of styrene and 2-vinyl pyridine, G3PS-g-P2VP, was synthesized by direct coupling of living P2VPLi to the precursor. The dendrimer-like copolymer of styrene and tert-butyl methacrylate, G3PS-g-PtBMA, was synthesized by an indirect procedure in which a living polymer containing mainly PtBMA segment was attached to the precursor. Both methods resulted in the formation of dendrimer-like copolymers with the high molecular weights (up to 8.5 × 106 Da), large molecular sizes (diameter up to 73 nm), and dense shells (number of arms up to 1300). These products, G3PS-g-P2VP and G3PS-g-PtBMA, were protonated with trifluoroacetic acid and acidic hydrolyzed, respectively. After transformation, amphiphilic dendrimer-like copolymers, G3PS-g-P2VPH+ and G3PS-g-PMAA, were obtained. Preliminary results on the solution properties of the amphiphilic products were presented.
Controlling Heat Transfer for the Manufacturing of High Molecular Weight Polyisobutylene via Formation of Micelles
Szilard Csihony, Nicole Janssen, Klaus Mühlbach
Corrected proof , doi: 10.1007/s10118-019-2250-z
[Abstract](282) [FullText HTML](175) [PDF 553KB](19)
An alternative cationic polymerization method is developed to produce high molecular weight polyisobutylene (HM-PIB) with molecular weights above 5 × 105 g/mol. The method involves micelle formation via functionalized low molecular weight polyisobutylene (LM-PIB) in non-polar solvent. One end of LM-PIB is modified with an imidazolium-containing ionic group, which together with the anion (e.g. Al2Cl7) works as Lewis acid. While the monomer isobutylene dissolves readily in non-polar solvent, polymerization can occur only within the micelle, which affords stable HM-PIB particles. HM-PIB with a molecular weight (MW) close to 1 × 106 g/mol was produced successfully with the described method.
Synthesis of Conjugated Polymers Containing Diketopyrrolopyrrole (DPP) Building Block and the Photophysical Study
Ying-Zhong Wu, Yi-Chen Zhang, Jia-Jun Chen, Li-Juan Fan
Corrected proof , doi: 10.1007/s10118-019-2248-6
[Abstract](301) [FullText HTML](158) [PDF 725KB](18)
Sonogashira coupling of two different diketopyrrolopyrrole (DPP)-containing dihaloarenes with the same aromatic bisalkyne resulted in two new conjugated polymers with the same backbone but different pendant groups on the DPP moiety. The polymers were found to have designed chemical structures via structural characterizations in comparison with three monomers. The molecular weight measurement further demonstrated the formation of polymers with polydispersity index around 2, consistent with the polycondensation nature of the polymerization based on Sonogashira coupling. Both polymers could dissolve in many organic solvents, and the one with long alkyl side group on DPP moiety had better solubility. Photophysical investigation showed that both polymers had typical absorption/emission of conjugated polymers, and varying the solvent did not have large influence. Compared with other polar solvents, toluene reduced the quantum yield of fluorescence of the polymers, especially for the one with long alkyl pedant group, accompanying with slight red-shift in absorption/emission. The difference in the absorption/emission wavelengths between the polymers was similar to that between the corresponding monomers. Adding water into the THF solution of polymers reduced the emission intensity but no red-shift was observed. Discussion about the structure-property relationships was carried out in detail.
Synthesis of a Rod-rod Diblock Copolymer, Poly(3-hexylthiophene)-block-poly(furfuryl isocyanate), through the Anionic Polymerization with an Oxyanionic Macroinitiator
Chang-Geun Chae, Joonkeun Min, In-Gyu Bak, Jae-Suk Lee
Corrected proof , doi: 10.1007/s10118-019-2243-y
[Abstract](257) [FullText HTML](170) [PDF 961KB](9)
A rod-rod diblock copolymer (diBCP), poly(3-hexylthiophene)-block-poly(furfuryl isocyanate) (P3HT-b-PFIC), was synthesized through the anionic polymerization with an oxyanionic macroinitiator of P3HT. The properties of the diBCP (molecular weight, dispersity, composition, thermal stability, UV-visible absorption, and thin film morphology) were determined by various analytical methods. P3HT-b-PFIC was blended with C60 in a toluene solution to prepare a thin film of binary electron donor/acceptor system. Such blending enabled partial conjugation of the two components by the Diels-Alder reaction between furan and C60 at 60 °C for 3 h; the mixture was then spin-cast as a thin film, and annealed at 250 °C for 24 h. Tapping-mode atomic force microscopy (AFM) revealed that P3HT and C60 domains had nanoscale interfaces without a large phase segregation. This result indicated that the microphase separation of C60-functionalized P3HT-b-PFIC preserved even at high temperature provided free C60 molecules with channels to diffuse on the sides of P3HT domain, thus preventing the macroscopic crystallization of free C60 through the interfacial stabilization.
Facile Synthesis of Functional Poly(ε-caprolactone) via Janus Polymerization
Huan Qiu, Zhe-Ning Yang, Jun Ling
Corrected proof , doi: 10.1007/s10118-019-2242-z
[Abstract](259) [FullText HTML](156) [PDF 1227KB](20)
Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable synthetic technique for functional poly(ε-caprolactone) (PCL) via Janus polymerization, which comprises cationic ring-opening copolymerization (ROP) of ε-caprolactone (CL) with 3,3-bis(chloromethyl) oxacyclobutane (CO) and (coordinated) anionic ROP of CL at a single propagating chain by rare earth metal triflates (RE(OTf)3) and propylene oxide, thus generating block copolymers in one step. The compositions of the copolymers of poly(CL-b-(CL-r-CO)) can be modulated by various RE(OTf)3. Scandium triflate catalyzes Janus polymerization to yield the copolymers containing the highest CO contents among all the RE(OTf)3 catalysts used with complete conversion of CL. The chlorine in CO repeating units is ready to be transferred into azide group which affords the modification sites to react with 9-ethynyl-9-fluorenol and mPEG-alkyne, respectively, via copper(I)-catalyzed azide-alkyne cycloaddition reaction with quantitative conversions of azides, as confirmed by FTIR analyses. According to NMR and SEC analyses, copolymers (PCC-g-PEG) bearing a homo-PCL block and a PEG-grafted block of poly(CO-co-CL) demonstrate well-defined chemical structures. The investigations on thermal properties reveal the strong phase separation between PCL and PEG blocks. The amphiphilic PCC-g-PEG is able to self-assemble into micelles in aqueous solution while cylindrical and lamellar morphologies are observed in bulk. We provide an efficient protocol to synthesize functional PCL combining one-step Janus polymerization and precise post-polymerization click reaction.
The Influence of Trans-1,4-poly(butadiene-co-isoprene) Copolymer Rubbers (TBIR) with Different Molecular Weights on the NR/TBIR Blends
Hao Wang, Ri-Guo Wang, Yun-Sheng Ma, Bo Luan, Ai-Hua He
Corrected proof , doi: 10.1007/s10118-019-2229-9
[Abstract](232) [FullText HTML](141) [PDF 866KB](7)
The molecular weight of a polymer is of prime importance and greatly influences the processing and mechanical properties of the polymer. Trans-1,4-poly(butadiene-co-isoprene) multi-block copolymer rubbers (TBIR) exhibit outstanding fatigue resistance, low heat build-up and good abrasion resistance, and are expected to be desirable candidate for high performance tire. Study on the influence of TBIR with different molecular weights on the structure and properties of TBIR and natural rubber (NR)/TBIR blends is essential to understand its contribution to the greatly improved dynamic properties of the rubber vulcanizates. TBIR with different molecular weights characterized by 1H-NMR, 13C-NMR, GPC, and DSC were highly trans-1,4-copolymers with similar chain sequence distribution and crystalline trans-1,4-polyisoprene (TPI) blocks. The green strength and modulus of TBIR increased with the increasing molecular weight. The NR/TBIR compounds filled with 40 phr carbon black were chemically cured by sulfur for the preparation of NR/TBIR vulcanizates. The compatibility between NR and TBIR, filler distribution, crosslinking bond and density, and properties of NR/TBIR vulcanizates were studied. The NR/TBIR vulcanizates showed increasing tensile strength, hardness, modulus, rebound, abrasion resistance, and flexural fatigue properties with increasing molecular weight of TBIR. Furthermore, they presented significant improvement in flexural fatigue resistance when compared with that of NR vulcanizate. The contribution mechanism of TBIR on the NR/TBIR blends was discussed. The TBIR with a wide range of molecular weight are ideal rubbers for high performance tires.
A Phenol-containing α-Diimine Ligand for Nickel- and Palladium-Catalyzed Ethylene Polymerization
Chen Tan, Wen-Min Pang, Chang-Le Chen
Corrected proof , doi: 10.1007/s10118-019-2232-1
[Abstract](416) [FullText HTML](148) [PDF 936KB](65)
A phenol-containing dibenzhydryl-based α-diimine ligand bearing hydroxy group on para-position of aniline moiety was designed, synthesized, and investigated in Ni- and Pd-catalyzed ethylene polymerization. The Ni complex bearing hydroxy groups resulted in not only high polyethylene molecular weight (Mn up to 1.5 × 106), but also significantly increased melting temperature (Tm up to 123 °C) and greatly decreased branching density (33/1000C) versus the Ni catalyst bearing OMe group on para-position of aniline moiety. This is consistent with the hypothesis that the deprotonation of the phenol moiety generated a phenoxide bearing strong electron-donating O substituent by methylaluminoxane (MAO) cocatalyst. The Pd complexes bearing hydroxy groups exhibited similar catalytic properties to those of the Pd catalyst bearing OMe groups did.
Regioselective Polymerizations of α-Olefins with an α-Diamine Nickel Catalyst
Heng Liao, Jie Gao, Liu Zhong, Hai-Yang Gao, Qing Wu
Corrected proof , doi: 10.1007/s10118-019-2227-y
[Abstract](328) [FullText HTML](171) [PDF 717KB](17)
Polymerizations of linear α-olefins (CnH2n, CH2=CH―R, R = Cn−2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains (Cn−2), while chain-straightening polymerizations of α-olefins with nickel-based catalysts produce semicrystalline polyolefins. Polymerizations of various α-olefins were carried out using an α-diamine nickel catalyst with a significantly distorted chelating ring. The influences of temperature, monomer concentration, and chain length of α-olefins on polyolefin microstructure were examined in detail. The α-diamine nickel catalyst realized highly regioselective 2,1-insertion of α-olefins regardless of reaction temperature and monomer concentration. Increased chain length of α-olefins led to the formation of more linear polyolefin. Semicrystalline polyolefins with high melting temperatures (Tm) were made from α-olefins through highly regioselective 2,1-insertion and precise chain-straightening.
Synthesis of Alkyne-functionalized Polymers via Living Anionic Polymerization and Investigation of Features during the Post-“thiol-yne” Click Reaction
Lin-Can Yang, Li Han, Hong-Wei Ma, Pi-Bo Liu, He-Yu Shen, Chao Li, Song-Bo Zhang, Yang Li
Corrected proof , doi: 10.1007/s10118-019-2203-6
[Abstract](490) [FullText HTML](164) [PDF 6630KB](23)
" Thiol-yne” click reaction has already been widely applied in synthesis and modification of new polymer structures or novel materials due to its specific features. However, in most studies, only chain-end strategy was employed when using the di-addition feature of thiol-yne reaction, thus the in-chain di-addition strategy could endow us with a broader space to develop the synthesis of advanced polymers. Therefore, in this paper, the features of in-chain mono- and di-addition were investigated when modifying the alkyne-functionalized polymers to prepare grafted polymers via thiol-yne click reaction. The results showed that it is almost impossible to obtain the in-chain di-adducts even under excess feeding of chain-end thiol-functionalized grafts, while only the in-chain mono-adducts could be obtained efficiently. Further researches investigated that the controlled grafting could be encountered when carrying out the thiol-yne click reaction between chain-end alkyne-functionalized polystyrenes and chain-end thiol-functionalized polystyrenes under proper feedings. Therefore, the effect of steric-hindrance might be the primary reason for the alternative grafting via thiol-yne click reaction between in-chain and chain-end alkyne-functionalized polymers.
A User-friendly Living Cationic Polymerization: Degenerative Chain-transfer Polymerization of Vinyl Ethers by Simply Using Mixtures of Weak and Superstrong Protonic Acids
Mineto Uchiyama, Masataka Sakaguchi, Kotaro Satoh, Masami Kamigaito
Corrected proof , doi: 10.1007/s10118-019-2233-0
[Abstract](239) [FullText HTML](133) [PDF 729KB](3)
Mixtures of a weak protonic acid and a trace amount of superstrong protonic acid were used for the simple control of the cationic polymerization of vinyl ethers via a degenerative chain-transfer mechanism, in which the former acid works as a precursor of the chain transfer agent (CTA) or the dormant species and the latter works as a source of the cationic propagating species. The addition of mixtures of phosphoric acid dibutyl ester ((n-BuO)2PO2H) or 1-octanethiol (n-C8H17SH) and a trace amount of trifluoromethanesulfonic acid (TfOH) to a solution of isobutyl vinyl ether (IBVE) at −78 °C resulted in polymers with controlled molecular weights, which were basically determined by the feed ratio of IBVE to the weak protonic acid, and narrow molecular weight distributions (Mw/Mn ≈ 1.1). These results were almost the same as those obtained using their prepared adducts of IBVE as CTAs in the presence of a trace amount of TfOH under similar conditions. Methanesulfonic acid (CH3SO3H), whose adduct of IBVE has not been isolated due to instability, was similarly used in conjunction with trace TfOH to result in controlled molecular weights but slightly broader MWDs (Mw/Mn = 1.2–1.8). These results indicate that the sulfoxonium ion is also an effective intermediate in the cationic DT polymerization in addition to the phosphonium and sulfonium intermediates derived from (n-BuO)2PO2H and n-C8H17SH, respectively. The simple living cationic polymerization was thus achieved by using a combination of a weak protonic acid and a trace amount of TfOH, which are both easily available, low cost, free from metal, and easy to handle, without need for preparation of the initiator.
Numerical simulation of the distribution function and free energy of a single wormlike polymer confined between hard walls
Yang Gu, Hui Zhang, and Dongliang Zhang
Accepted Manuscript , doi: 10.1007/s10118-019-2322-0
[Abstract](80) [PDF 655KB](1)
We focus on the distribution and free energy of a wormlike polymer confined between two parallel hard walls. The variation in the distribution and free energy of the wormlike chain as the spacing between the walls decreases (or as the total contour length of the wormlike chain increases or as the persistence length of the chain increases) is simulated. The main reason for these changes is a degradation of the long wormlike chain into a Gaussian long chain under weak confinement.
The location-influenced fluorescence of AIEgens in the microphase-separated structures
Yafang Zhi, Chao Li, Zehua Song, Zhongjia Yang, Hongwei Ma, and Longcheng Gao
Accepted Manuscript , doi: 10.1007/s10118-020-2338-5
[Abstract](23) [PDF 329KB](1)
When the fluorescent AIEgens are selectively located in nanostructures of a block copolymer, the fluorescence properties are highly influenced by the surrounding structural relaxation. Not only the main relaxation but also the secondary relaxation induces the corresponding fluorescence transitions. These results would promote the understanding of the interrelation between fluorescence probes and the nanostructures.
Copolymerization of Azobenzene Bearing Monomer and 3,4-Ethylene Dioxythiophene (EDOT): Improved Electrochemical Performance for Electrochromic Device Applications
Serife O. Hacioglu
Accepted Manuscript , doi: 10.1007/s10118-019-2306-0
[Abstract](141) [PDF 2466KB](7)
In this study, novel electrochromic copolymers of 3,4-ethylenedioxythiophene (EDOT) and (E)-1,2-bis(2-fluoro-4-(4-hexylthiophen-2-yl)phenyl)diazene (M1) with different monomer feed ratios were designed and synthesized via electrochemically. Electrochemical and spectroelectrochemical characterizations were performed by using voltammetry and UV-Vis-NIR spectrophotometer techniques to test the applicability of copolymers for electrochromic applications. In terms of electrochemical behaviors, addition of an electron rich EDOT unit into the azobenzene comprising copolymer increased the electron density on the polymer chain and resulting copolymers with very low oxidation potentials at around 0.30 V. While the homopolymers (P1 and PEDOT) exhibited neutral state absorptions centered at 510 nm and 583 nm, EDOT bearing copolymers showed red shifted absorptions compared to those of P1 with lower optical band gaps. In addition, the poor optical contrast and switching times of azobenzene bearing homopolymer were significantly improved with EDOT addition into the copolymer chain. As a result of promising electrochromic and kinetic preperties, CoP1.5 bearing single layer electrochromic device which works between purple and light greenish blue colors were constructed and characterized.
Poly(methyl methacrylate) induced microstructure and hydrolysis behavior changes of poly(L-lactic acid)/carbon nanotubes composites
Xu Yu, Xin-zheng Jin, Ting Huang, Nan Zhang, Xiao-yu Li, Yong Wang
Accepted Manuscript , doi: 10.1007/s10118-019-2323-z
[Abstract](96) [PDF 2109KB](2)
Poly(L-lactic acid) (PLLA)-based composites exhibit wide applications in many fields. However, most of hydrophilic fillers usually accelerate the hydrolytic degradation of PLLA, which is unfavorable for the prolonging of the service life of the articles. In this work, a small quantity of poly(methyl methacrylate) (PMMA) (2-10 wt%) was incorporated into the PLLA/carbon nanotubes (CNTs) composites. The effects of PMMA content on the dispersion of CNTs, the microstructure and the hydrolytic degradation behaviors of the composites were systematically investigated. The results showed that PMMA promoted the dispersion of CNTs in the composites. Amorphous PLLA was obtained in all the composites. Largely enhanced hydrolytic degradation resistance was achieved by incorporating PMMA, especially at relatively high PMMA content. Incorporating 10 wt% PMMA leaded to the dramatic decrease of the hydrolytic degradation rate from 0.19 %/h of the PLLA/CNT composite sample to the 0.059 %/h of the PLLA/PMMA-10/CNT composite sample. The microstructure evolution of the composites was also detected, and the results showed that no crystallization occurred in the PLLA matrix. Further results based on the interfacial tension calculation showed that the enhanced hydrolytic degradation resistance of the PLLA matrix was mainly attributed to the relatively stronger interfacial affinity between PMMA and CNTs, which prevented the occurrence of hydrolytic degradation at the interface between PLLA and CNTs. This work provides an alternative method to tailor the hydrolytic degradation ability of the PLLA-based composites.
Effect of Butyl α Hydroxymethyl Acrylate Monomer Structure on the Morphology Produced via Aqueous Emulsion Polymerization-Induced Self-Assembly
Shou-kuo Man, Xiao Wang, Jin-wen Zheng, and Ze-sheng An
Accepted Manuscript , doi: 10.1007/s10118-019-2303-3
[Abstract](134) [PDF 1968KB](9)
Polymerization-induced self-assembly (PISA) is an efficient and versatile method to afford polymeric nano-objects with polymorphic morphologies. Compared to dispersion PISA syntheses based on soluble monomers, the vast majority of emulsion PISA formulations using insoluble monomers leads to kinetically-trapped spheres. Herein, we present aqueous emulsion PISA formulations generating worms and vesicles besides spheres. Two monomers with different butyl groups, n-butyl (nBHMA) and tert-butyl (tBHMA) α-hydroxymethyl acrylate, and thus different water solubility were synthesized via Baylis-Hillman reaction. Photoinitiated aqueous emulsion polymerizations of nBHMA and tBHMA employing poly(ethylene glycol) macromolecular chain transfer agents (macro-CTAs, PEG45-CTA and PEG113-CTA) at 40 °C were systematically investigated to evaluate the effect of monomer structure and solubility on the morphology of the generated block copolymer nano-objects. Higher order morphologies including worms and vesicles were readily accessed for tBHMA, which has a higher water solubility than nBHMA. This study proves that plasticization of the core-forming block by water plays a key role in enhancing chain mobility required for morphological transition in emulsion PISA.
Photo-grafting Poly(acrylic acid) onto Poly(lactic acid) Chains in Solution
Jiaxing Wang, Yanbin Huang, and Wantai Yang
Accepted Manuscript , doi: 10.1007/s10118-019-2308-y
[Abstract](115) [PDF 1427KB](8)
Poly(lactic acid) (PLA) is one of the most important bio-plastics, and chemical modification of already-polymerized poly(lactic acid) chains may enable optimization of its material properties and expand its application areas. In this study, we demonstrated that poly(lactic acid) can be readily dissolved in acrylic acid at room temperature, and acrylic acid can be graft polymerized onto poly(lactic acid) chains in solution with the help of photoinitiator benzophenone under 254 nm ultraviolet (UV) irradiation. Similar photo-grafting polymerization of acrylic acid (PAA) had only been studied before in the surface modification of polymer films. The graft ratio can be controlled by various reaction parameters, including irradiation time, benzophenone content, and monomer/polymer ratios. This photo-grafting reaction resulted in high graft ratio (graft ratio PAA/PLA up to 180%) without formation of homopolymers of acrylic acid. When the PAA/PLA graft ratio was higher than 100%, the resulted PLA-g-PAA polymer was found dispersible in water.The pros and cons of the photo-grafting reaction were also discussed.
Unsymmetric side chains of indacenodithiophene copolymers lead to improved packing and device performance
Ying Yang, Tong Shan, Jian Cao, Hua-Chun Wang, Ji-Kang Wang, Hongliang Zhong, Yun-Xiang Xu
Accepted Manuscript , doi: 10.1007/s10118-020-2342-9
[Abstract](1) [PDF 1010KB](0)
Two conjugated polymers (PuIDTBD and PuIDTQ) with unsymmetric side chains have been prepared for polymer solar cells with two other polymers (PIDTBD and PIDTQ) with symmetric side chains as control compounds. The combination of methyl and 4-hexylphenyl side chains on the same bridged carbon can ensure good solubility, decrease π-π stacking distances and bring proper miscibility with PC71BM simultaneously. Therefore, the corresponding polymer solar cells (PSCs) based on donor polymers with unsymmetric side chains exhibit enhanced short-circuit current density (Jsc) and power conversion efficiency (PCE) compared with control polymers. The PIDTBD and PIDTQ based devices gave low PCE of 2.13% and 1.48%, while those of PuIDTBD and PuIDTQ were improved to 3.93% and 4.12%. The results demonstrate that unsymmetric side chain engineering of conjugated polymers is an effective approach to achieve high performance PSCs.
Activity enhancement of MgCl2-supported Ziegler-Natta catalysts by Lewis-Acid pre-treatment for ethylene polymerization
Matthieu Humbert, Sébastien Norsic, Jean Raynaud, Vincent Monteil
Accepted Manuscript , doi: 10.1007/s10118-019-2335-8
[Abstract](72) [PDF 878KB](8)
Ziegler-Natta precatalysts were synthetized from Lewis-base-modified-MgCl2 supports and treated by various Lewis acids, prior to activation by triethylaluminum, in order to increase their activity in ethylene polymerization. BCl3 provided the highest increase in activity. Interestingly, polymerization results showed no substantial modification of polymer properties, which is consistent with the Lewis acid only promoting the creation of new active sites, after activation by TEA, possessing very similar features than the original ones achievable with conventional precatalysts (i.e. without Lewis-acid treatment).
Competition between liquid-liquid demixing, crystallization and glass transition in solutions of PLA of different stereochemistry and DEET
Chanita Sungkapreecha, Walter W. Focke, and René Androsch
Accepted Manuscript , doi: 10.1007/s10118-019-2314-0
[Abstract](109) [PDF 801KB](5)
Liquid-liquid (L-L) de-mixing and vitrification of solutions of either crystallizable poly (L-lactic acid) (PLLA) or non-crystallizable poly (D/L-lactic acid) (PDLLA) with 50 m-% N, N-diethyl-3-methylbenzamide (DEET) were analyzed by calorimetry and cloud-point measurements, allowing drawing conclusions about the effect of the polymer stereochemistry on the phase behavior. Regardless of the PLA stereochemistry, vitrification of the solutions on fast cooling, hindering crystallization of PLLA, occurred below -20 °C and suppressed prior L-L de-mixing. The experimental results prove that crystallization in samples containing crystallizable PLLA, observed at around 55 °C on slow cooling, is not preceded by L-L de-mixing.
Enhanced Mechanical Properties of Poly(arylene sulfide sulfone) Membrane by co-Electrospinning with Poly(m-xylene adipamide)
Lu Chen, Xinlin Tuo, Xichuan Fan, Chunjie Xie, Bao-Hua Guo, Jian Yu, Ping Hu, and Zhao-Xia Guo
Accepted Manuscript , doi: 10.1007/s10118-019-2297-x
[Abstract](135) [PDF 1332KB](2)
The mechanical properties of poly(arylene sulfide sulfone) (PASS) electrospun membrane were significantly enhanced by co-electrospinning with semi-aromatic nylon poly(m-xylene adipamide) (MXD6), another engineering plastic with high thermal stability and good mechanical properties. The tensile strength of PASS membrane increased with increased incorporation of MXD6, and was tripled when 20% MXD6 was incorporated. The mechanism of the mechanical property improvement is the existence of hydrogen bonding interaction between PASS and MXD6 and between adjacent fibers at the intersections. The thermal properties of the PASS/MXD6 membranes were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), showing that the membranes can be stably utilized up to 180 ℃ without any change in appearance and without decomposition. The contact angle measurements of all the membranes showed hydrophobic character. To demonstrate the potential applications of PASS/MXD6 blend membranes, their oil absorption capacities were evaluated with three oils of different viscosities, proving that the PASS/MXD6 membranes are better absorbents than commercial non-woven polypropylene fibers. Therefore, PASS/MXD6 fibrous membranes produced by electrospinning have a great potential in practical applications.
Chloromethylation and quaternization of poly(aryl ether ketone sulfone)s with clustered electron-rich phenyl groups for anion exchange membranes
Lei Xiong, Yuanfang Hu, Zigui Zheng, Zailai Xi, Dongyang Chen
Accepted Manuscript , doi: 10.1007/s10118-020-2340-y
[Abstract](29) [PDF 1677KB](5)
Ion segregation is critically important to achieve high ion conductivity for anion exchange membranes (AEMs). Herein, a new bisphenol monomer bearing ten electron-rich phenyl groups is designed and polymerized with various amounts of electron-deficient 4,4’-dihydroxydiphenylsulfone and 4,4’-difluorobenzophenone to yield dense and selective reaction sites for chloromethylation and quaternization. As the most challenging step, the chloromethylation is optimized by tuning the reaction temperature, reaction time, and reactant ratios. The ion exchange capacity, water uptake, anion conductivity, mechanical stability, and alkaline stability of the resulting AEMs are characterized in detail. It is found that the chloromethylation reaction needs to be carried out at low equivalent of chloromethylation agents to avoid undesirable crosslinking. The QA-PAEKS-20 with an IEC of 1.19 mmol g-1 exhibits a Cl― conductivity of 11.2 mS cm-1 and a water uptake of 30.2% at 80 °C, which are promising for AEM applications.
Phthalonitrile Resins Derived from Vanillin: Synthesis, Curing Behavior and Thermal Properties
Yue Han, Dong-Hao Tang, Guang-Xing Wang, Ya-Nan Sun, Ying Guo, Heng Zhou, Wen-Feng Qiu, and Tong Zhao
Accepted Manuscript , doi: 10.1007/s10118-019-2311-3
[Abstract](139) [PDF 1597KB](5)
Vanillin was used as sustainable source for phthalonitrile monomer synthesis, and allyl/propargyl ether moieties were introduced to improve the processability at the minimal cost of thermal properties. The synthesis route was optimized to minimize side-reactions and simplify post-processing, and the monomers were obtained in high purities and good yields. The curing behavior, mechanism and processability of the monomers were studied, and the thermal properties of cured polymers were evaluated. Of the two monomers, the allyl ether containing one exhibited a wide processing window of 185 oC, and was mainly cured into phthalocyanine and linear aliphatic structures through self-catalytic curing process. Also the glass transition temperature was higher than 500 oC. On the contrary, the propargyl ether containing monomer could be only partially cured, and compromise in heat resistance was found. Compared with traditional petroleum-based phthalonitrile resins, the bio-based monomers could be cured without addition of catalysts, and improvement in processability was achieved at no cost of thermal performances.
Fast Computation of Electrostatic Interactions for a Charged Polymer with Applied Field
Hao Lin, Zi-Tong Lei, Ming-Ming Ding, Hong-Jun Wang, and Tong-Fei Shi
Accepted Manuscript , doi: 10.1007/s10118-020-2343-8
[Abstract](0) [PDF 920KB](0)
Using a hybrid simulation approach that combines a finite difference method with a Brownian dynamics, we investigated the motion of charged polymers. Owing to the fact that polymer-solution systems often contain a large number of particles and the charged polymer chains are in a state of random motion, it is a time-consuming task to calculate the electrostatic interaction of the system. Accordingly, we propose a new strategy to shorten the CPU time by reducing the iteration area. Our simulation results illustrate the effect of preset parameters on CPU time and accuracy, and demonstrate the feasibility of the “local iteration” method. Importantly, we find that the increase in the number of charged beads has no signicant influence on the time of global iterations and local iterations. For a number of 80×80×80 grids, when the relative error is controlled below 1.5%, the computational efficiency is increased by 8.7 times in the case of containing 500 charged beads. In addition, for a number of 100×100×100 grids with 100 charged beads, the computational efficiency can be increased up to 12 times. Our work provides new insights for the optimization of iterative algorithms in special problems.
Review in Structural Design and Application of Azo-based Supramolecular Polymers Systems
Hui-Tao Yu, Jun-Wen Tang, Yi-Yu Feng, and Wei Feng
Accepted Manuscript , doi: 10.1007/s10118-019-2331-z
[Abstract](75) [PDF 3108KB](19)
This manuscript presents a brief overview of recent advances in azo-containing supramolecular systems. In the literature, it has been shown that azo supramolecular polymers and their composite materials have fast and intelligent responsiveness to various external stimuli, such as temperature, pH change, redox reagents, ligands, coupling reagents, etc. In applications, these systems are widely used for molecular motors, shape memory, liquid crystal, solar thermal energy storage, signal transmission, intelligent encryption and other purposes. Furthermore, these systems are a key issue for device upgrade processing. However, the design and rules of azo supramolecular polymers are still not supported by an exact theory. Information about the relationship between the spatial structure and behavior is lacking, and new supramolecular materials cannot be designed by adding functional moieties to known azo polymers. Based on the current research status, this review mainly summarizes the structural design principles, structures and applications of known azo supramolecules, while highlighting the emerging development fields, recent advances and prospects in fabricating self-assembling intelligent supramolecular systems with azo supramolecular polymers as responsive units. The goal is to bring new inspiration to researchers who want to optimize the chemical structure, steric conformation, electrostatic environment, and specific molecular functionalization.
Tailoring the Properties of Diels-Alder Reaction Crosslinked High-Performance Thermosets by Different Bismaleimides
Kai-ju Luo, Li-bo Huang, Yan Wang, Jun-rong Yu, Jing Zhu and Zu-ming Hu
Accepted Manuscript , doi: 10.1007/s10118-019-2328-7
[Abstract](17) [PDF 3878KB](2)
A series of Diels-Alder reaction cross-linked thermosets with recyclability and healability were prepared from furan-containing aromatic polyamide and bismaleimides with different chemical structures. The structures of synthesized bismaleimides were confirmed by 1H nuclear magnetic resonance (1H-NMR) and their reversible cross-linking with the furanic polyamide were detected by 1H-NMR and sol-gel transition. The dynamic mechanical analysis and tensile test revealed the variable thermal and mechanical properties of thermosets cross-linked by different bismaleimides and different molar ratio of maleimide group to furan group (Ima/fur). The tensile test also demonstrated the better recyclability and solvent-assisted healability of thermosets cross-linked by more flexible bismaleimides. This work is expected to provide valuable information for design of recyclable and healable high-performance thermosets with desired properties.
Simulation Study on the Extension of Semi-flexible Polymer Chains in Cylindrical Channel
Yu Fu, Fan Wu, Jian-Hua Huang, Ying-Cai Chen, Meng-Bo Luo
Accepted Manuscript , doi: 10.1007/s10118-019-2291-3
[Abstract](154) [PDF 741KB](9)
The scaling relations among the mean end-to-end distance of polymer along the channel , the polymer length N, and the effective diameter of channel De, were investigated for flexible and semi-flexible polymer chains confined in long cylindrical channels. For the flexible polymer chain, scaling relation ~ NDe0.7 was found in the classic de Gennes regime at lp2/b < De < Rg with lp the persistence length, b the bond length and Rg the radius of gyration of polymer. For the semi-flexible polymer, ~ NDe1 in the transition regime lp < De < xlp (x > 1) and ~ De0.7 in the classic de Gennes regime at larger De > xlp were observed. The simulation results revealed that the scaling relation in the transition regime was due to the rod-like behavior of the semi-flexible polymer in the small regime lp < De < xlp.
Combining Neutron Scattering, Deuteration Technique and Molecular Dynamics Simulations to Study Dynamics of Protein and Its Surface Water Molecules
Lirong Zheng, Liang Hong
Accepted Manuscript , doi: 10.1007/s10118-019-2312-2
[Abstract](173) [PDF 2118KB](15)
Protein internal dynamics is essential for its function. Exploring the internal dynamics of protein molecules as well as its connection to protein structure and function is a central topic in biophysics. However,the atomic motions in protein molecules exhibits a great degree of complexities. These complexities arise from the complex chemical composition and superposition of different types of atomic motions on the similar time scales, and render challenging the explicit understanding of the microscopic mechanism governing protein motions, functions and their connections. Here, we demonstrated that, by using neutron scattering, molecular dynamics simulation and deuteration technique, one can address this challenge to a large extent.
Cross-linked Polyamides Prepared through Direct Bulk Michael Addition and Polycondensation from 1,6-Hexaxnediamine and Methyl Acrylate
Sheng-qing Yang, Jin-nan Zhao, Jing-bo Zhao, Zhi-yuan Zhang, and Jun-Ying Zhang
Accepted Manuscript , doi: 10.1007/s10118-019-2332-y
[Abstract](61) [PDF 1818KB](2)
Cross-linked polyamides (cPAs) were prepared through direct bulk Michael addition and subsequent polycondensation. Several mixed hexanediamine multi-esters (HDAMEs) were generated through the Michael addition of 1,6-hexanediamine (HDA) and methyl acrylate (MA) at 50 °C with different HDA/MA molar ratios. Melt polycondensation of HDAMEs followed at 150 °C or 170 °C in flasks to obtain viscous fluids, and curing was continued in tetrafluoroethylene molds to obtain cPA films. The Michael addition was monitored on the basis of FT-IR and ESI-MS spectra. The cPA films were characterized by DSC, TGA, dynamic mechanical analysis, and tensile test. These directly prepared cPAs exhibited Tg of 1–39 °C, tensile strength of up to 45 MPa, and strain at break from 18% to 40%. The cPAs with high tensile strength and good toughness were successfully synthesized through the direct bulk Michael addition from HDA and MA followed with polycondensation.
Facile Synthesis of Functional Poly(methyltriazolylcarboxylate)s by Solvent- and Catalyst-Free Butynoate-Azide Polycycloaddition
Weiwen Chi, Rongyuan Zhang, Ting Han, Jian Du, Hongkun Li, Weijie Zhang, Yongfang Li, and Ben Zhong Tang
Accepted Manuscript , doi: 10.1007/s10118-019-2316-y
[Abstract](87) [PDF 1082KB](19)
The copper-catalyzed and metal-free azide–alkyne click polymerizations have become efficient tools for polymer synthesis. However, the 1,3-dipolar polycycloadditions between internal alkynes and azides are rarely employed to construct functional polymers. Herein, the polycycloadditions of dibutynoate (1) and tetraphenylethene-containing diazides (2) are carried out at 100 oC for 12 h under solvent- and catalyst-free conditions, producing soluble poly(methyltriazolylcarboxylate)s (PMTCs) with high molecular weights in high yields. The resultant polymers are thermally stable with 5% weight loss emperatures up to 377 oC. The PMTCs show aggregation-induced emission (AIE) properties. They can work as fluorescent sensors for detecting explosive with high sensitivity, and generate two-dimensional fluorescent photopatterns with high resolution. Furthermore, their triazolium salts can be utilized for cell-imaging applications.
Polyester-supported chitosan-polyvinylidene fluoride-Material oxide composites with improved flame retardancy and thermal stability
Ahmed Abed, Nabil Bouazizi, Stéphane Giraud, Ahmida El Achari, Christine Campagne, Olivier Thoumire, Reddad El Moznine, Omar Cherkaoui, Julien Vieillard, Abdelkrim Azzouz
Accepted Manuscript , doi: 10.1007/s10118-020-2336-7
[Abstract](51) [PDF 1828KB](6)
Polyester (PET) was pre-activated by atmospheric air plasma and coated by various material oxide (MOx) such as titanium dioxide (TiO2), zinc oxide (ZnO) and silicon oxide (SiO2), using polyvinylidene fluoride (PVDF) and chitosan (CT) as binders. The resulting PET-PVDF-MOx-CT composites were thermally compressed and then characterized through scanning electron microposcopy, Fourier Infrared Spectroscopy, thermal gravimetric analysis and Flame Retardancy (FR) ability tests. PET modifications resulted in more thermal stability and less harmful composites with weaker hazardous gas release. This was explained in terms of structure compaction that blocks pyrolysis gas emissions. CT incorporation was found to reduce the material ability to oxidation. This judicious procedure also allowed tailoring improved flame retardancy ability, by lengthening the combustion delay and slowing the flame propagation. Chitosan also turned out to contribute to a possible synergy with the other polymers present in the synthesized materials. These results provide valuable data that allow understanding the FR phenomena and envisaging low-cost high FR materials from biodegradable raw materials.
Dendronized polymers with high FTC-chromophore loading density: large second-order nonlinear optical effects, good temporal and thermal stability
Meng Jin, Zhaochen Zhu, Qiuyan Liao, Qianqian Li, and Zhen Li
Accepted Manuscript , doi: 10.1007/s10118-019-2307-z
[Abstract](141) [PDF 659KB](12)
In this paper, two new dendronized nonlinear optical (NLO) polymers were synthesized with high FTC chromophore loading density by the introduction of high generation chromophore dendrons on the side chains. Due to their suitable molecular weights, both of them possess good solubility in common solvents. They also inherited the advantages of dendrimers (large NLO coefficient), especially for PG2, its NLO coefficient d33 value was as high as 282 pm V-1. Also, it had the good temporal stability with 80% of its maximum value being retained at the temperature as high as 129 oC
Directed self-assembly of vertical PS-b-PMMA nanodomains grown on multilayered polyelectrolyte films
Kai Liu, Chunming Yang, Boming Yang, Lan Zhang, Wenchao Huang, Xiaoping Ouyang, Fugang Qi, Nie Zhao, Fenggang Bian
Accepted Manuscript , doi: 10.1007/s10118-019-2315-z
[Abstract](138) [PDF 1514KB](13)
Layer-by-layer polyelectrolyte self-assembly, a common method for preparing high-quality ultra-thin films, was employed to direct polystyrene-block polymethylmethacrylate (PS-b-PMMA) block copolymer self-assembly behaviour for the first time. Differing from previous neutral polymer brushes anchored to silicon substrates via chemical modification, polyelectrolyte multilayers (PEMs) were anchored by electrostatic interaction and provided a stable, smooth, and neutral interface. In the present study, PS-b-PMMA was deposited on polyacrylamide hydrochloride/polyacrylic acid (PAH/PAA) PEMs prepared by layer-by-layer self-assembly to successfully yield vertical nanodomains after thermal annealing. Seven layered PEMs revealed an excellent, smooth surface, with a low roughness of 0.6 nm. The periodic structure with interlamellar spacing was determined by grazing-incidence small-angle X-ray scattering (GISAXS) to be 47 nm. The morphology of the PS-b-PMMA nanodomains depended on the polyanion-to-polycation concentration ratio, which is related to the interaction between the block copolymer and the substrate. Our results demonstrate that layer-by-layer self-assembly is a helpful method for the phase separation of block polymers and the fabrication of vertical, ordered nanodomains.
Bio-based and Biodegradable Electrospun Fibers Composed of Poly(L-lactide) and Polyamide 4
Tao Chen, Guocheng Zhong, Yuanting Zhang, Liming Zhao, Yongjun Qiu
Accepted Manuscript , doi: 10.1007/s10118-019-2299-8
[Abstract](148) [PDF 1674KB](5)
Novel bio-based and biodegradable block copolymers were synthesized by “click” reaction between poly(L-lactide) (PLLA) and polyamide 4 (PA4). Upon tuning the mole mass of PLLA block, the properties of copolymers and electrospun ultrafine fibers were investigated and compared with those of PLLA and PA4 blends. PLLA and PA4 were found incompatible and formed individual crystalline regions, along with reciprocal inhibition in crystallization. Electrospun fibers were highly hydrophobic, even if the hydrophilic PA4 was rich. The crystallinity of either PLLA or PA4 decreased after electrospinning and PLLA-rich as-spun fibers were almost amorphous. Immersion tests proved that fibers of block copolymers were relatively homogeneous with micro-phase separation between PLLA and PA4. The fibrous structures of copolymers were different from those electrospun from blends, for which sheath-core structure induced by macro-phase separation between homopolymers of PLLA and PA4 was confirmed by TEM, EDS and XPS.
Synthesis of Polyurethane/Poly(urea-formaldehyde) Double-shelled Microcapsules for Self-healing Anticorrosion Coatings
Yan Song, Kaifeng Chen, Jingjing Wang, Yuan Liu, Tao Qi, Guo Liang Li
Accepted Manuscript , doi: 10.1007/s10118-019-2317-x
[Abstract](131) [PDF 2078KB](5)
One-component, catalyst-free self-healing coatings with double-shelled polymer microcapsules have drawn considerable attention due to wide applications. In this work, the synthesis parameters of double-shelled polymer microcapsules and the mechanism of the self-healing process was systematically investigated. Apart from the chemical structure of the microcapsule shell, the thickness of the shell, the size of the microcapsules and the core fraction affect the self-healing anticorrosion properties. The synthesis parameters were further optimized in terms of the agitation rate, pH, weight ratio of core to shell and temperature. Under these conditions, the microcapsule shell consisted of a rough surface formed by poly(urea-formaldehyde) and a smooth inner wall by polyurethane. The size of the microcapsules and core fraction were calculated to be approximately 30 μm and 75%, respectively. The self-healing anticorrosion coating incorporating the as-synthesized microcapsules exhibited corrosion resistance in artificially scratched areas, which were further characterized by electrochemical impedance spectroscopy.
Synthesis of an Azobenzene-Containing Main-Chain Crystalline Polymer and Photodeformation Behaviors of Its Supramolecular Hydrogen- Bonded Fibers
Zhengzheng Wang and Huiqi Zhang
Accepted Manuscript , doi: 10.1007/s10118-019-2302-4
[Abstract](137) [PDF 975KB](10)
The synthesis of a new azobenzene (azo)-containing main-chain crystalline polymer with reactive secondary amino groups in its backbone and photodeformation behaviors of its supramolecular hydrogen-bonded fibers are described. This main-chain azo polymer (namely Azo-MP6) was prepared via the first synthesis of a diacrylate-type azo monomer and its subsequent Michael addition copolymerization with trans-1,4-cyclohexanediamine under the mild reaction condition. Azo-MP6 was found to have a linear main-chain chemical structure instead of a branched one, as verified by comparing its 1H NMR spectrum with the 1H NMR spectrum of the azo polymer prepared via the polymer analogous reaction of Azo-MP6 with acetic anhydride. The thermal stability, phase transition behavior, and photoresponsivity of Azo-MP6 were characterized with TGA, DSC, POM, XRD, and UV-vis. The experimental results revealed that it has good thermal stability, low glass transition temperature, broad crystalline phase temperature range, and highly reversible photoresponsivity. Physically crosslinked supramolecular hydrogen-bonded fibers with good mechanical properties and a high alignment order of azo mesogens were readily fabricated for Azo-MP6 by using the simple melt spinning method, and they could show “reversible” photoinduced bending under the same UV light irradiation and good anti-fatigue properties.
Truxene-Based Conjugated Microporous Polymers via Different Synthetic Methods
Mengyang Wang, Qiujing Zhang, Qiaoqiao Shen, Qingyin Li, and Shijie Ren
Accepted Manuscript , doi: 10.1007/s10118-019-2321-1
[Abstract](106) [PDF 1410KB](5)
Four truxene-based conjugated microporous polymers (Tr-CMPs) were prepared via different synthetic methods and their structure-property relationships were studied. The polymer networks have high Brunauer-Emmett-Teller (BET) specific surface areas ranging from 554 to 1024 m2 g-1. Pore sizes of the CMPs with different linkers are mainly located between 0.60 and 1.96 nm. Among all the Tr-CMPs, Tr-CMP4 has the highest BET surface area of 1024 m2 g-1 and exhibits the highest H2 uptake of 0.88 wt%. Tr-CMP2 prepared by Suzuki-Miyaura coupling reaction has the highest photoluminescence quantum yields (PLQYs) of 13.06 % and CO2 uptake of 6.25 wt%.
A Facile Strategy for Non-Fluorinated Intrinsic Low-k and Low-Loss Dielectric Polymers: Valid Exploitation of Secondary Relaxation Behaviors
Chao Qian, Zhenguo Fan, Weiwen Zheng, Runxin Bei, Tianwen Zhu, Siwei Liu, Zhenguo Chi, Matthew. P. Aldred, Xudong Chen, Yi Zhang, and Jiarui Xu
Accepted Manuscript , doi: 10.1007/s10118-020-2339-4
[Abstract](26) [PDF 930KB](2)
High-performance low-k and low-loss circuit materials are urgently needed in the field of microelectronics due to the upcoming Fifth-Generation Mobile Communications Technology (5G Technology). Herein, a facile design strategy for non-fluorinated intrinsic lowk and low-loss polyimides is reported by fully consideration of the secondary relaxation behaviors of the polymer chains. A new amorphous non-fluorinated polymer (TmBPPA) with a k value of 2.23 and a loss tangent of less than 3.94 × 10-3 at 104 Hz has been designed and synthesized, which to the best of our knowledge is the lowest value amongst the non-fluorinated and non-porous polymers reported in the literature. Meanwhile, TmBPPA exhibits excellent overall properties, such as excellent thermostability, good mechanical properties, low moisture absorption, and high bonding strength. As high-performance flexible circuit materials, all these characteristics are urgently needed for present and future high density, high speed and high frequency electronic circuit designs for 5G wireless networks.
Nanoparticle Dispersion and Glass Transition Behavior of Polyimide-Grafted Silica Nanocomposites
Shani Hu, Yu Lin, Guozhang Wu
Accepted Manuscript , doi: 10.1007/s10118-019-2300-6
[Abstract](195) [PDF 1347KB](8)
How to control the spatial distribution of nanoparticles to achieve different performance requirements is a constant challenge in the field of polymer nanocomposites. Current studies have been focused on the flexible polymer chain systems. In this study, the rigid polyimide (PI) chain grafted silica particles with different grafting chain lengths and grafting density were prepared by “grafting to” method, and the influence of polymerization degree of grafted chains (N), matrix chains (P) and grafting density (σ) on the spatial distribution of nanoparticles in the PI matrix was reported. Besides, the glass transition temperature (Tg) of PI composites was systematically investigated. The results show that silica particles are well dispersed in polyamic acid composite systems, while appear aggregation and small clusters in PI nanocomposites after thermal imide. Besides, the particle size has no impact on the spatial distribution of nanoparticles. When σ·N0.5 << (N/P)2, the grafted and matrix chains interpenetrate, and the frictional resistance of the segment increases, resulting in restricted relaxation kinetics and Tg increase of the PI composite system. In addition, smaller particle size and longer grafted chains are beneficial for improving Tg of composites. These results are all propitious to complete the microstructure control theory of nanocomposites and make a theoretical foundation for the high performance and multi-function of PI nanocomposites.
Mediating the Migration of Mesenchymal Stem Cells by Dynamically Changing the Density of Cell-Selective Peptides Immobilized on Beta-cyclodextrin-modified Cell-resisting Polymer Brushes
Wang Du, Deteng Zhang, Xuemei Wang, Tanchen Ren, Changyou Gao
Accepted Manuscript , doi: 10.1007/s10118-019-2324-y
[Abstract](85) [PDF 3354KB](0)
Dynamic control of mesenchymal stem cells (MSCs) behaviors on biomaterial surface is critically involved in regulating the cell fate and tissue regeneration. Herein, a stimuli-responsive surface based on host-guest interaction with cell selectivity was developed to regulate migration of MSCs in situ by dynamic display of cell-specific peptides. Azobenzene-grafted MSC-affinitive peptides (EPLQLKM, Azo-E7) were grafted to ß-cyclodextran (-CD)-modified poly(2-hydroxyethyl methacrylate)-b-poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (PHG) brushes, which were prepared by using surface-initiated atom transfer radical polymerization (SI-ATRP). X-ray photoelectron spectroscopy (XPS), quartz crystal microbalance (QCM) and water contact angle were used to characterize their structure and property. Cell adhesion assay showed that the combination effect of resisting property of PHG and MSC-affinity of E7 could promote the selective adhesion of MSCs over other types of cells such as RAW264.7 macrophages and NIH3T3 fibroblasts to some extent. UV-vis spectroscopy proved that the competing guest molecules, amantadine hydrochloride (Ama), could release Azo-E7 peptides from the CD surface to different extents, and the effect was enhanced when UV irradiation was employed simultaneously. As a result, the decrease of cell adhesion density and migration rate could be achieved in situ. The cell density and migration rate could be reduced by over 40% by adding 20 μM Ama, suggesting that this type of surface is a new platform for dynamic regulation of stem cell behaviors in situ.
Hofmeister effect on thermo-responsive poly(N-isopropylacrylamide) hydrogels grafted on macroporous polyvinyl alcohol formaldehyde sponges
Kai Shi, Di Sha, Jiu-duo Xu, Xu Yang, Bao-long Wang, Yan-xiong Pan, Xiang-ling Ji
Accepted Manuscript , doi: 10.1007/s10118-019-2320-2
[Abstract](110) [PDF 4965KB](7)
In this work, the Hofmeister effects of nine kinds of anions at different concentrations on the lower critical solution temperature (LCST) of the macroporous thermo-responsive poly(N-isopropylacrylamide) grafted polyvinyl alcohol formaldehyde (PVF-g-PNIPAM) hydrogels are investigated with differential scanning calorimetry (DSC). Four kinds of anions with strong hydration, including CO32-, SO42-, S2O32- and F-, and four kinds of anions with weak hydration, including Br-, NO3-, I- and ClO4-, and Cl- as a medium anion are systematically investigated to demonstrate the effects of the residual hydroxyl groups and network structure of PVF on the LCST of PVF-g-PNIPAM hydrogels in comparison with that of pure PNIPAM. On the one hand, the existence of hydroxyl groups of PVF backbone promotes the grafted PNIPAM solubility due to their hydrophilicity and hydrogen-bond interactions with water. On the other hand, the network structure of as-prepared samples restricts free movements of grafted PNIPAM chains, which results in the increase of LCST values. In addition, the difference of grafting percentage also influences the tendency of LCST values of PVF-g-PNIPAM hydrogels under salt concentration.
Monolithic Covalent Organic Framework Aerogels through Framework Crystallization Induced Self-Assembly: Heading towards Framework Materials Synthesis over All Length Scales
Wei Zhao, Tianpin Wang, Jiali Wu, Ruping Pan, Xiangyang Liu and Xikui Liu
Accepted Manuscript , doi: 10.1007/s10118-019-2313-1
[Abstract](91) [PDF 2660KB](21)
Here through the synergism between kinetic dynamic imine-exchange control and thermodynamic control, rarely observed compressible, porous, crystalline COF aerogels were synthesized, the mechanism behind is a framework crystallization induced self-assembly (FCISA) process. The prepared COF aerogel possess extremely high BET surface over 2000 m2/g and high maximum equilibrium adsorption capacity of bisphenol-A as 699 mg/g in aqueous solution.
Selective Carbon Dioxide Capture in Antifouling Indole-based Microporous Organic Polymers
Mengqi Du, Yuzheng Peng, Yuanchi Ma, Li Yang, Yuanlin Zhou, Fankun Zeng, Xiangke Wang, Manling Song, Guanjun Chang
Accepted Manuscript , doi: 10.1007/s10118-019-2326-9
[Abstract](101) [PDF 1475KB](4)
Intermolecular synergistic adsorption of indole and carbonyl groups induced by intermolecular hydrogen bondings makes microporous organic polymer (PTICBL) exhibit high CO2 uptake capacity (5.3 mmol/g at 273K) and selectivities (CO2/CH4 = 53, CO2/N2 = 107 at 273K). In addition, we find that indole units in the PTICBL networks inhibit the attachment of bacteria (E. coil and S. aureus) on the surface of PTICBL and extend its service life in CO2 capture.
Fluorescent Supramolecular Polymersomes Based on Pillararene/Paraquat Molecular Recognition for pH-Controlled Drug Release
Run Zhao, Yujuan Zhou, Kecheng Jie, Jie Yang, Sébastien Perrier, Feihe Huang
Accepted Manuscript , doi: 10.1007/s10118-019-2305-1
[Abstract](112) [PDF 4860KB](5)
Researchers have put significant efforts on developing versatile fluorescent polymeric systems due to their promising biological/biomedical labelling, tracking, monitoring, imaging, and diagnostic applications. However, complicated organic/polymeric synthesis or post modification of these functionalized platforms is still a big obstacle for their further application and thereby provides clear motivation for exploring alternative strategies for the design and fabrication of easily available fluorescent systems. The marriage of supramolecular polymers and fluorescent imaging can provide a facile and dynamic manner instead of tedious and time-consuming synthesis due to the dynamic and reversible nature of noncovalent interactions. Herein, based on water-soluble pillararene/paraquat molecular recognition, we successfully prepare two amphiphilic polypseudorotaxanes which can self-assemble into supramolecular polymersomes in water. These polymersomes can be reversibly destroyed and reformed by tuning the solution pH. Attributing to the aggregation-induced emission of tetraphenylethylene groups, high fluorescence can be introduced into the obtained supramolecular polymersomes. Furthermore, pH-triggerd release of an encapsulated water-insoluble drug (doxorubicin) from the self-assembled fluorescent supramolecular polymersomes is also investigated.
Crystallization behavior and dynamic mechanical properties of poly(ε-caprolactone)/octaisobutyl-polyhedral oligomeric silsesquioxanes composites prepared via different methods
Siqi Teng, Zhiguo Jiang, Zhaobin Qiu
Accepted Manuscript , doi: 10.1007/s10118-019-2333-x
[Abstract](58) [PDF 650KB](7)
Two octaisobutyl-polyhedral oligomeric silsesquioxanes (oib-POSS) reinforced biodegradable poly(ε-caprolactone) (PCL) composites were prepared via two different methods, i.e., melt compounding and solution casting, which were named as mPCL/oib-POSS and sPCL/oib-POSS, respectively, in this work. Oib-POSS dispersed finely in both composites; moreover, oib-POSS aggregates were larger in mPCL/oib-POSS than in sPCL/oib-POSS. Despite preparation methods, oib-POSS obviously promoted the crystallization of PCL, especially in sPCL/oib-POSS, but did not modify the crystal structure of PCL. The storage moduli of PCL were improved significantly in both composites. PCL/oib-POSS composites with enhanced crystallization behavior and improved dynamic mechanical properties were successfully prepared through both methods; moreover, the solution casting method was more effective than the melt compounding method.
(Arylimido)vanadium(V)-Alkylidene Complexes as Catalysts for Ring-Opening Metathesis Polymerization (ROMP) of Cyclic Olefins: Ligand Design for Exhibiting the High Activity
Kotohiro Nomura and Sapanna Chaimongkolkunasin
Accepted Manuscript , doi: 10.1007/s10118-019-2298-9
[Abstract](125) [PDF 1277KB](1)
(Imido)vanadium(V)-alkylidene complexes of type, V(CHSiMe3)(NR)(OR’)(PMe3)2 [R = Ad, C6H5, 2,6-Me2C6H3, 2,6-Cl2C6H3; R’ = 2,6-Me2C6H3, 2,6-iPr2C6H3, 2,6-F2C6H3, C6F5, C6Cl5], exhibited from moderate to remarkable catalytic activities for ring-opening metathesis polymerization (ROMP) of norbornene (NBE). The catalytic activities were affected by the ligand substituents, and V(CHSiMe3)(N-2,6-Cl2C6H3)(OC6X5)(PMe3)2 (X = F, Cl) demonstrated the exceptionally high catalytic activities for ROMP of NBE. The complexes polymerized cycloheptene (CHPE) and cis-cyclooctene (COE), and the ROMP of COE by the OC6Cl5 analogue proceeded in a living manner even at 80 ºC, and the activity increased with increasing the temperature up to 120 ºC. Highly active catalysts for ROMP of cyclic olefins (NBE, cyclopentene, CHPE) can be generated in situ by premixing isolated V(CHSiMe3)(NC6F5)(O-2,6-iPr2C6H3)(PMe3)2 with 1.0 equiv of C6F5OH or C6Cl5OH via the immediate phenoxy exchange; the activity was affected by the kind of phenol added [TOF in the ROMPs of NBE: 46200 min-1 (upon addition of C6F5OH) vs 37.3 min-1 (none)].
Mechanism of Janus polymerization: A DFT study
Tianwen Bai, Xufeng Ni, Jun Ling, Zhiquan Shen
Accepted Manuscript , doi: 10.1007/s10118-019-2318-9
[Abstract](89) [PDF 1039KB](2)
Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including (1) fast cationic polymerization with slow anionic one, (2) fast anionic polymerization with dormant cationic one, and (3) reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory (DFT) calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results.
Efficient Addition Polymerization of Norbornene with Polar Norbornene Derivatives by Neutral Nickel (II) Catalysts
Ling Guo, Yan-Ping Zhang, Hong-Liang Mu, Li Pan, Kai-Ti Wang, Huan Gao, Bin Wang, Zhe Ma, Yue-Sheng Li
Accepted Manuscript , doi: 10.1007/s10118-019-2292-2
[Abstract](167) [PDF 932KB](5)
A series of nickel complexes {4a: [(2,6-iPr2C6H3)N=CHC16H12O]Ni(Me)(Py), 4b:[(2,6-iPr2C6H2OCH3)N=CHC16H12O]Ni(Me)(Py), 4c:[(2,6-iPr2C6H2Cl)N=CHC16H12O]Ni(Me)(Py) and 4d: [(2,6-iPr2C6H2CF3)N=CHC16H12O]Ni(Me)(Py)} based on β-ketiminato ligands bearing various an electron-donating or electron-withdrawing substituent on the para-position of the aniline group were synthesized and unambiguously characterized. The X-ray crystallographic analysis showed that complexes 4b and 4d adopted a near-square-planar geometry, and the anilines bearing a para-OMe or -CF3 group found to be situate on the axial position of the metal center. All complexes exhibited high activities up to 1.251.35 × 107 gPNB⋅molNi-1⋅h-1 toward norbornene (NBE) addition polymerization (conversion > 91.2% in 2 min) under low loading of B(C6F5)3 (B/Ni=3) at 30 C, affording polymers with high molecular weight up to 2.543.18 × 106. Different levels of decrease in catalytic activities could observed of all catalysts as the reaction temperature increased, while 4d bearing a strong electron-withdrawing -CF3 group showed the highest activity at 70 C, while others exhibited notable decrease in catalytic activity with the raise in reaction temperature. Complexes 4a-d showed remarkable tolerance to polar groups and could efficiently promote the copolymerization of NBE with its polar derivatives, including NBE bearing small acetate and hydroxyl group, as well as bulky oligomers, yielding copolymers with high functional NBE incorporations. Novel NBE copolymers with high functional comonomer incorporations and improved solubility were obtained in high yields.

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2019, 37(8) .  
[Abstract](53) [PDF 63025KB](2)
Direct-writing Structure Color Patterns on the Electrospun Colloidal Fibers toward Wearable Materials
Shu-Jian Yuan, Wei-Hao Meng, Ai-Hua Du, Xin-Yu Cao, Yong Zhao, Jing-Xia Wang, Lei Jiang
2019, 37(8): 729 -736.   doi: 10.1007/s10118-019-2286-0
[Abstract](101) [FullText HTML](19) [PDF 0KB](1)
This study presents a direct-writing structure color patterns on electrospun colloidal fibers by inkjet printing. The colloidal fiber was obtained by electrospinning the aqueous mixture of colloidal particles of poly(styrene-methyl methacrylate-acrylic acid) and poly(vinyl alcohol). The pattern was obtained by directly inkjet printing water onto the electrospun colloidal fiber. The pattern formation was attributed to the morphological transition of the colloidal fiber from the fiber aggregation to latex aggregation and the corresponding color change due to the dissolution of poly(vinyl alcohol) by water. Interestingly, a clear and clean image was successfully obtained on the ethanol-treated colloidal fibers film in comparison to a confused and blur image onto the freshly-made film. It is because the treatment process can compact the fiber structure and lower the spreading/wetting behavior of ink on the fiber structure, contributing to the formation of high-quality pattern. Various letters or quick response code were flexibly designed and printed on to colloidal fibers. Furthermore, the pattern can be easily transferred onto flexible substrate, i.e., a flexible printed bracelet. This work will be of great significance for the development of novel wearable functional materials/devices based on electrospun colloidal fibers.
One-step Production of Continuous Supercapacitor Fibers for a Flexible Power Textile
Yang Hong, Xun-Liang Cheng, Ge-Jun Liu, Dong-Sheng Hong, Si-Si He, Bin-Jie Wang, Xue-Mei Sun, Hui-Sheng Peng
2019, 37(8): 737 -743.   doi: 10.1007/s10118-019-2301-5
[Abstract](175) [FullText HTML](67) [PDF 746KB](11)
Given that conventional bulky electrochemical energy storage devices are too rigid and heavy to be considered wearable, developing fully integrated power systems is expected to accelerate the successful commercialization of smart electronic textiles. Although great achievements have been made for fiber-shaped energy storage devices, there remain key challenges pertaining to their fabrication efficiency, scalability, and stability. Herein, a general and highly efficient method is developed to continuously fabricate supercapacitor fibers with lengths of kilometers at high production rate up to 118 m/h through a simple one-step wet spinning method. Beneficial from the designed unique two-circle-in-one-circle architecture, the resulting supercapacitor fibers demonstrated high electrochemical stability even after being bended for 1 × 105 cycles. As a demonstration, these continuous supercapacitor fibers were further woven into a flexible power scarf for large-scale applications in wearable electronics. This simple and scalable fabrication process combined with the unique structure provides a general and effective paradigm to design other fiber-shaped devices like sensors, batteries, and solar cells.
Block Copolymer Colloidal Particles with Unique Structures through Three-dimensional Confined Assembly and Disassembly
Jiang-Ping Xu, Jin-Tao Zhu
2019, 37(8): 744 -759.   doi: 10.1007/s10118-019-2294-0
[Abstract](336) [FullText HTML](90) [PDF 92633KB](13)
Structured block copolymer (BCP) particles have gained increasing attention due to their potential applications in separation, catalysis, controlled release, and other fields. Three-dimensional (3D) confined assembly has been proved as a facile yet robust approach for generating BCP particles with controllable shapes and internal structures. In this feature article, we summarized the preparation of structured polymeric particles through 3D confined self-assembly of BCPs. The effects of interfacial interactions, degree of confinement, and additives on the shape and internal structure of BCP microparticles were comprehensively discussed. In addition, we highlighted the recent progress in using disassembly as a route to synthesize colloidal particles with unique structures. Two strategies were introduced in this part: (a) disassembling the discrete domains resulted in mesoporous microparticles; (b) disassembling the continuous domains led to the dissociation of microparticles into micelle-like nano-objects. The applications of the structured colloidal particles in photonic crystals, controlled release, and directed growth of inorganic materials were also presented. Finally, we discussed the current challenges and future opportunities in this promising area.
Optimization of Ethylene Glycol Doped PEDOT:PSS Transparent Electrodes for Flexible Organic Solar Cells by Drop-coating Method
Hui-Qin Cui, Rui-Xiang Peng, Wei Song, Jian-Feng Zhang, Jia-Ming Huang, Li-Qiang Zhu, Zi-Yi Ge
2019, 37(8): 760 -766.   doi: 10.1007/s10118-019-2257-5
[Abstract](291) [FullText HTML](156) [PDF 4187KB](14)
Fabrication of flexible transparent electrodes (FTEs) is one of the core technologies in the field of flexible electronics. Among multiple choices of FTEs, poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid) (PEDOT:PSS) has shown its promising application in roll-to-roll manufacturing. A simple yet effective method for substantially boosting the conductivity of these conducting polymer films without causing large-domain aggregations is by adding ethylene glycol (EG) as dopant. Herein, we investigated in detail the effects of the secondary solvent of ethylene glycol (EG) on the optical and electrical characteristics of PEDOT:PSS films. The modified PEDOT:PSS FTEs were deposited using drop-coating techniques as it had greater compatibility for large-area samples than the conventional spin-coating method did. The 6% EG-doped PEDOT:PSS FTE via drop-coating method achieved a high figure of merit (FoM) value of 47.24 and the devices fabricated using the optimal PEDOT:PSS FTE yielded a high power conversion efficiency (PCE) of 8.89%, mostly attributed to the modified PEDOT:PSS films that had excellent optical and electrical characteristics with low surface roughness. These results suggested that EG-doping could effectively boost the conductivity of PEDOT:PSS films and that the modified PEDOT:PSS FTE is suitable for roll-to-roll manufacturing in the future.
Controllable Emission via Tuning the Size of Fluorescent Nano-probes Formed by Polymeric Amphiphiles
Xiao-Cheng Wang, Shi-Xin Zhou, Lan Ding, Yu-Han Zhao, Shen-Xi Min, Bin Dong, Bo Song
2019, 37(8): 767 -773.   doi: 10.1007/s10118-019-2256-6
[Abstract](317) [FullText HTML](186) [PDF 786KB](33)
Incorporating fluorophores into polymeric nanoparticles has been testified as a feasible way to improve the emitting property and bio-compatibility of nano-emitters, which can be applied as fluorescent probes in labeling cells for imaging. Plenty of efforts have been made on the above direction. However, the size effect of nano-emitters has not been addressed yet mainly given the difficulties in controlling morphology and size of the assemblies. In our preceding study, we employed post-polymerization modification method for preparing amphiphilic copolymers, and obtained core-shell (the hydrophobic fluorophores are wrapped inside the nanoparticle to form the core) assemblies in aqueous solution. By this method, we are able to regulate the ratio of the hydrophilic/hydrophobic moieties, and thus alternate the size of the assemblies in a rather simple way. In this study, we synthesized a series of random copolymers by changing the ratio of poly(ethylene glycol) to tetraphenylethylene groups. Notably, the number of repeating units of the polymer was controlled constant for all the copolymers. The self-assembly of these copolymers resulted in different sizes of nanoparticles, and the size decreased with the decreasing fraction of poly(ethylene glycol). Interestingly, the emission of the nanoparticles showed size dependence, and smaller diameter corresponded to stronger emission. Being cultured with HeLa cells, either the large (diameter of ~300 nm) or the small (diameter of ~180 nm) nano-emitters allowed for very high cell viabilities up to 25 μg·mL−1. Both of them can be applied in cell imaging and provide high contrast fluorescent images.
Synthesis and Physico-chemical Properties of (Co)polymers of 2-[(2E)-1-methyl-2-buten-1-yl]aniline and Aniline
A. Andriianova, A. Shigapova, Y. Biglova, R. Salikhov, I. Abdrakhmanov, A. Mustafin
2019, 37(8): 774 -782.   doi: 10.1007/s10118-019-2261-9
[Abstract](209) [FullText HTML](118) [PDF 1059KB](15)
A new soluble polymer on 2-[(2E)-1-methyl-2-buten-1-yl]aniline and its copolymers with aniline basis have been synthesized in various molar ratios. For all samples, the electrical conductivity, morphology, solubility, electrochemical properties, as well as spectral and molecular mass characteristics have been studied, and a comparative analysis with polyaniline has been carried out. The substituent introduced into the aniline aromatic ring significantly improves the solubility in typical organic solvents of a high molecular weight product. The morphology of the test compounds depends on the co-monomer ratio. As the content of the substituted aniline in the initial mixture increases, the morphology of the polymer changes from the inherent polyaniline fibrous microstructure to the globular one with irregular substituted polyaniline shapes and sizes. Electrochemical study of the samples revealed that the higher the oxidation potential, the wider the band gap (ranging from 2.00 to 2.15). The electrical conductivity decreases in proportion to the increase in the substituted aniline concentration of the initial co-monomer mixture and amounts to 12.5–35.7 × 106 nSm.
Synthesis of Cerium-containing Polymethylphenyl Silicone and Its Antioxidant Effect on Fluorosilicone Rubber
Yong Guan, Jian Hu, Yong-Kang Huang, Yang You, Huan-Yao Zhang, An-Na Zheng, Xiang Xu, Da-Fu Wei
2019, 37(8): 783 -789.   doi: 10.1007/s10118-019-2266-4
[Abstract](206) [FullText HTML](118) [PDF 742KB](3)
As an essential elastomer used in edge technologies, fluorosilicone rubber (FSR) suffers serious oxidative ageing problem when serving at high temperature. Cerium oxide is generally used as an antioxidant additive but remains unsatisfactory. In order to obtain better antioxidant effect on improving the thermal stability of FSR, a kind of cerium-containing polymethylphenyl silicone (PSI-Ce) was synthesized and the structure was verified by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR). Due to the homogeneous dispersion on molecular scale, PSI-Ce imposed much better antioxidant effect than the commercial CeO2 did, no matter from isothermal degradation at 320 °C or thermal-oxidative ageing test at 230 °C. In particular, after ageing for 72 h, FSR/PSI-Ce (2 phr) maintained 82% of tensile strength and 63% of elongation at break, in comparison to the corresponding values of 48% and 42% for FSR/CeO2 (2 phr). Moreover, 2 phr PSI-Ce was equivalent to 0.046 phr CeO2 according to cerium element conservation.
Degradable Protein-loaded Polymer Capsules Fabricated by Thiol-disulfide Cross-linking Reaction at Liquid-liquid Interface
Xiaoteng Ma, Guangda Han, Hanying Zhao
2019, 37(8): 790 -796.   doi: 10.1007/s10118-019-2253-9
[Abstract](326) [FullText HTML](171) [PDF 795KB](15)
In these years, the encapsulation of proteins for protection and delivery purpose has attracted great interest. In this research, W/O emulsion droplets were used as soft templates and bovine serum albumin (BSA) encapsulated hollow capsules were prepared by liquid-liquid interfacial thiol-disulfide exchange reaction. Block copolymer chains with pendant pyridyl disulfide groups are located at liquid-liquid interface, and upon addition of a macromolecular crosslinking agent with multiple pendant thiol groups into an emulsion, thiol-disulfide interfacial crosslinking reactions lead to the formation of BSA encapsulated hollow capsules. The cleavage of disulfides on the membranes results in the degradation of hollow structures and the release of encapsulated protein molecules. Transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and confocal laser scanning microscopy were employed to characterize the hollow capsules. In comparison with native BSA, BSA molecules encapsulated in the hollow structures show higher catalytic efficiency due to higher local concentration of reactants in the structures. The membranes of the hollow capsules can efficiently protect the encapsulated BSA from hydrolysis by trypsin.
Ultrasmall Nanoparticles Diluted Chain Entanglement in Polymer Nanocomposites
Sheng-Chao Chai, Tian-Yang Xu, Xiao Cao, Gang Wang, Quan Chen, Hao-Long Li
2019, 37(8): 797 -805.   doi: 10.1007/s10118-019-2262-8
[Abstract](424) [FullText HTML](199) [PDF 2661KB](63)
Nanoparticle-polymer composites exhibit unusual mechanical properties and chain dynamics when the nanoparticle size is smaller than the entanglement mesh size of the matrix polymer chains, corresponding to the ultrasmall regime defined by de Gennes. However, the mechanism is still ambiguous due to the lack of suitable model systems. Here, we develop an ultrasmall nanoparticle system by using a bimodal grafting strategy to graft both short alkyl chains and long polystyrene chains onto the polyoxometalate molecular nanoparticles with a tunable repulsive potential between the nanoparticles, thus facilitating their uniform dispersion in polystyrene matrices. Linear viscoelasticity of the resultant nanocomposites changes with increasing the filler content, which shows a decrease in both plateau modulus and terminal relaxation time, indicative of a dilution effect of the nanoparticles. Namely, the entanglement network becomes sparser with increasing the filler content.
Preparation and Properties of Ultrathin Flexible Expanded Graphite Film via Adding Natural Rubber
Yan-Ling Mo, Yu-Xin Tian, Yu-Hang Liu, Feng Chen, Qiang Fu
2019, 37(8): 806 -814.   doi: 10.1007/s10118-019-2264-6
[Abstract](231) [FullText HTML](103) [PDF 922KB](20)
Expanded graphite (EG) films exhibit potential use in a wide field including thermal management, conductive applications, and electromagnetic interference (EMI) shielding. However, their poor tensile strength and brittleness are crucial deficiencies for commercial applications. To address these defects, in our work, natural rubber (NR) is employed to improve EG films for better mechanical strength and flexibility. The origin of the strengthening effect of EG films by the addition of natural rubber mainly arises from the formation of a simulate shell structure. Compared to the neat EG films, the addition of merely 2 wt% NR can give rise to superior ductility. Further, the loading of 10 wt% NR realizes a significant mechanical enhancement of the EG/NR films, i.e., 2.4 and 11.4 times increase in tensile strength and elongation at break, respectively. Besides, EG/NR films containing 10 wt% NR can still sustain excellent thermal and electric conductivities of 173 W·m−1·K−1 and 75 S·cm−1, respectively. Furthermore, a very high EMI of 41.4 dB is achieved as the film thickness reaches 50 μm. Thus, the lightweight EG/NR films with comprehensive performance as well as their virtue of green and simple large-scale preparation endow them with the possibility of designing next-generation flexible electronics.
Fabrication of 6FDA-HFBAPP Polyimide Asymmetric Hollow Fiber Membranes and Their CO2/CH4 Separation Properties
Cong-Jun Gan, Xiao-Chen Xu, Xue-Wei Jiang, Feng Gan, Jie Dong, Xin Zhao, Qing-Hua Zhang
2019, 37(8): 815 -826.   doi: 10.1007/s10118-019-2255-7
[Abstract](299) [FullText HTML](186) [PDF 1273KB](13)
In this work, poly(amide acid) solution, the precursor of polyimide, was synthesized by the reaction of 4,4′-(hexafluoroisopropylidene)diphthalicanhydride and 2,2-bis[4-(4-aminophenoxy)phenyl]-hexafluoropropanane in the solvent of N-methyl-2-pyrrolidone (NMP) and tetrahydrofuran (THF). Then, hollow fiber membranes for high flux gas separation were prepared by dry-jet wet spinning using the precursor solution of poly(amide acid) as the spinning dope and a subsequent imidization process. Silicone rubber was further coated outside the obtained hollow fiber membranes to repair the defects on the denser layer. The effects of internal, external coagulation bath ratios with air gap, and coating solution concentrations on the morphologies, structures, and separation performance of the membranes were studied. Results showed that the sponge-like support layer was formed when the content of NMP was increased from 50% to 90% in the internal coagulation bath. The outer surface of the membrane became denser when the water content in the external coagulation bath increased from 40% to 100%, and the separation coefficient of CO2/CH4 increased by 2 times. This value could reach up to 1.4 when the air gap was 6 cm. With tuning the mass fraction of silicone rubber as 5%, hollow fiber composite membranes with uniform coating layer and an improved separation coefficient of 5.4 could be obtained.
Analysis of Dimer Impurity in Polyamidoamine Dendrimer Solutions by Small-angle Neutron Scattering
Tian-Fu Li, Yi-Yun Cheng, Yu Wang, Hui Wang, Dong-Feng Chen, Yun-Tao Liu, Li Zhang, Wen-Ze Han, Rong-Deng Liu, Zi-Jun Wang, Chun-Ming Yang, Charl J. Jafta, Daniel Clemens, Uwe Keiderling
2019, 37(8): 827 -833.   doi: 10.1007/s10118-019-2260-x
[Abstract](256) [FullText HTML](143) [PDF 578KB](11)
Dimer impurity in the solution of a generation five (G5) polyamidoamine (PAMAM) dendrimer has been investigated by small-angle neutron scattering (SANS). The existence of dimer impurity in dendrimer solution was evidenced by indirect Fourier transform (IFT) analysis of the SANS data, in which the maximum dimension of particles in solution was found to be about twice the diameter of G5 dendrimer. We then developed an analytical model which accounts for the scattering contribution from both dendrimer monomer and dimer. The experimental data were well fitted by using the established model. The results showed that the amount of dimer impurities is significant for the measured three batches of G5 PAMAM dendrimers.
Research on the Glass Transition Temperature and Mechanical Properties of Poly(vinyl chloride)/Dioctyl Phthalate (PVC/DOP) Blends by Molecular Dynamics Simulations
Jing Li, Shao-Hua Jin, Guan-Chao Lan, Zi-Shuai Xu, Lu-Ting Wang, Na Wang, Li-Jie Li
2019, 37(8): 834 -840.   doi: 10.1007/s10118-019-2249-5
[Abstract](320) [FullText HTML](172) [PDF 630KB](26)
To effectively improve the performance and expand the applications of polymers, molecular dynamics (MD) simulations with the COMPASS force field have been applied to predict the miscibility, glass transition temperature (Tg), and mechanical properties of poly(vinyl chloride)/dioctyl phthalate (PVC/DOP) blends. The solubility parameter values obtained are in good agreement with the reference data and the little difference (|Δδ| < 2.0 MPa0.5) between two components indicates that PVC/DOP is a miscible system. Tg is predicted by the slope of the free volume and density versus temperature simulation data based on density and free volume theory which is agree well with the experimental data. In addition, the analyses of mechanical properties results indicate that the values of Young’s modulus (E), bulk modulus (K), and shear modulus (G) decrease with the addition of DOP, demonstrating that the rigidity of material is weakened and the ductility is improved. The mechanical properties can also be effectively improved by increasing the temperature, which may provide a more flexible mixture, with lower E, K, G but an increased ductility.