Dynamic Monte Carlo simulations of bulk lattice polymers driven through planar geometries with sequentially converging, parallel and diverging spaces between two neutrally repulsive solid plates are reported. The spatial profiles of polymer velocity and deformation along the course of such a laminar extensional flow have been carefully analyzed. The results appear consistent with experimental observations in literature. In the entrance and exit regions, a linear dependence of chain extension upon the excess velocity has been observed. Moreover, an annexed shear flow and a molecular-dispersion effect are found. The results demonstrate a useful strategy of this approach to study polymer flows and bring new insights into the non-Newtonian-fluid behaviors of bulk polymers in capillary rheometers and micro-fluidic devices.

The effect of clay on the morphology and phase-separation behavior of poly(methyl methacrylate)/poly(styreneco-acrylonitrile) (PMMA/SAN) blends and the variation of clay dispersion have been investigated. With the evolution of phase separation in PMMA/SAN, most of the clays are first located at the boundaries between PMMA and SAN, and then gradually move to the PMMA-rich domain, owing to the affinity of clay to PMMA. The introduction of clay causes the increase of binodal and spinodal temperatures of PMMA/SAN and enlarges their metastable region, indicating the phase stabilizing effect of clay on the matrix. But the influence of clay on the cloud points obviously depends on the composition of PMMA/SAN. The selective adsorption of PMMA on the clay results in the difference between the composition of surface layer and that of polymer matrix. Hence, the clay plays the role of an agent changing the conditions of phase structure formation.

A water-soluble, polythiophene-based colorimetric sensor was designed for selective and sensitive detection of carbenicillin in HEPES buffer solution. Quaternized quinine was linked to thiophene through bis-functionality benzyl group, which can interact with carbenicillin via electrostatic interaction and geometric match effect. The sensor exhibited a colorimetric signal change upon the addition of carbenicillin because of the formation of more nonplanar structures. However, the addition of other beta-lactam antibiotics or dicarboxylic acids into the sensor solution caused no obvious changes in absorbance intensity ratio. This result may be attributed to the cavity formed by the semi-rigid framework of PTQ2, which is suitable for the special binding with carbenicillin. This novel sensor can effectively distinguish carbenicillin from other beta-lactam antibiotics and has a wide linear range response in HEPES buffer solution. Linear calibration curves are obtained with 0 to 18 μmol/L of HEPES buffer solution, with a limit of detection of 0.54 μmol/L.

The crowding agent induced phase transition of amphiphilic block copolymers in solution was explicitly considered. The influence of the size and the volume fraction of the crowding agent on the phase separation of amphiphilic diblock copolymers is investigated by using self-consistent field theory (SCFT) method. The concentration of the disorder to order transition of the block copolymer decreases when the size of the crowding agent is larger than that of the solvent. The higher volume fraction of the crowding agent will induce the transition of the block copolymer from disorder to order state at a lower concentration. The relation between the size and the volume fraction of the crowding agent is elucidated. When the size of the crowding agent is larger, its volume fraction of the disorder to order transition of the block copolymer will be lower. The conformation of the crowding agent considered as a polymer chain is also studied and compared.

Diphenyl (4-hydroxyphenyl) hexadecyl phosphonium bromide (POH) -modified montmorillonite (POHMMT) was used to prepare a novel TiCl₄/MgCl₂/POHMMT compound catalyst and exfoliated iPP/POHMMT nanocomposites were prepared by the in situ intercalative polymerization of propylene with the TiCl₄/MgCl₂/POHMMT compound catalyst. The POH surfactants don’t change the catalytic characteristic of the Z-N catalyst and the obtained PP presents high isotacticity, normal molecular weight and molecular weight distribution. The WAXD, SAXS and TEM results demonstrate the highly exfoliated iPP/POHMMT nanocomposites were produced by the in situ polymerization with this novel catalyst, while the intercalated iPP/ Na⁺MMT nanocomposites were produced with the TiCl₄/MgCl₂/Na⁺MMT compound catalyst. Through this approach, in situ propylene polymerization can actually take place between the silicate layers and lead not only to PP with high isotacticity and molecular weight, but also to highly exfoliated PP nanocomposites.

Cell adhesion plays a key role in various aspects of biological and medical sciences. In this study, poly(N-isopropylacrylamide) (PNIPAM) was grafted on polystyrene surfaces using different solvents under UV radiation. Moreover, the relation between surface roughness and cell adhesion were evaluated by gravimetric, SEM, AFM, contact angle measurement and cellular analyses. The gravimetric analysis clearly indicated an increase in the grafting by adding 10% methanol to water. The study of surface topography by AFM images showed an increase in the surface roughness and as a result of which, a decrease in wettablity was observed. At 37 ℃, epithelial cells were well attached and proliferated on the grafted surfaces, while these cells were spontaneously detached below 32 ℃ in the absence of any enzymes. Moreover, MTT assay and SEM images indicated good cell viability and an increase in cell adhesion caused by the roughness increase. The results of this study reveal the great potential of PNIPAM-grafted polystyrene for being used in the biomedical fields such as drug delivery systems, tissue engineering and cell separation.

In this work, a specific polylactide (PLA) 4032D was melt-mixed with a new toughener: butyl acrylate (BA), ethyl acrylate (EA) and glycidyl methacrylate (GMA) copolymer (BA-EA-GMA). DMA tests showed that PLA/BA-EA-GMA blends were partially miscible. The degree of crystallinity of PLA increased while the cold crystallization temperature shifted to higher temperatures with increasing BA-EA-GMA content. The SEM micrographs showed that PLA/BA-EA-GMA blends had a good dispersion and this phenomenon was in good agreement with their higher impact strength. The result showed that the adding of BA-EA-GMA has enhanced the flexibility of PLA/BA-EA-GMA blends as compared with pure PLA. The impact strength was changed from 3.4 kJ/m2 for pure PLA to 29.6 kJ/m² for 80/20 PLA/BA-EA-GMA blend.

Two series of poly(imide-ester)s (PIEs) and poly(ether-imide-ester)s (PEIEs), having benzoxazole or benzothiazole pendent groups, were conveniently prepared by the diphenylchlorophosphate-activated direct polyesterification of two bis(imide-carboxylic acid)s (1), such as 2-[3,5-bis(N-trimellitimidoyl)phenyl]benzoxazole (1_O) and 2-[3,5-bis(Ntrimellitimidoyl) phenyl]benzothiazole (1_S) and two bis(imide-ether-carboxylic acid)s (2), such as 2-[3,5-bis(4-trimellitimidophenoxy)-phenyl]benzoxazole (2_O), and 2-[3,5-bis(4-trimellitimidophenoxy)-phenyl]benzothiazole (2_S) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. The structures, solubilities and thermal properties of obtained polymers were investigated in detail. All of the resulting polymers were characterized by FTIR and ¹H-NMR spectroscopy and elemental analysis. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, tetrahydrofuran and m-cresol, as well as in polar organic solvents, such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide. The modified polymers were obtained in quantitative yields with inherent viscosities between 0.47 and 0.67 dl⋅g⁻¹. Experimental results indicated that all the polymers had glass transition temperature between 198 ℃ and 262 ℃, the decomposition temperature at 10% weight loss between 398 ℃ and 531 ℃ under nitrogen.

Polyethylene oxide (PEO)-polyvinylpyrrolidone (PVP) blended Na⁺ ion conducting solid polymeric membranes: (1−x) [75PEO:25NaPO₃] + x PVP, where 0 < x < 12 wt%, are reported. The polymeric blending was done using a solvent-free hot-press method. Two orders of conductivity enhancement (σca. 1.07 × 10⁻⁵ S⋅cm⁻¹) have been achieved with 3 wt% of PVP (i.e. the composition: [97(75PEO:25NaPO₃) + 3PVP]), from that of the pure host: (75PEO:25NaPO3). The conductivity enhancement in PEO-PVP blended solid polymeric membranes have been explained by the ionic conductivity, ionic mobility and mobile ion concentration measurements. Materials characterization and polymer-salt complexation were done with the help of X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) studies. The temperature dependent conductivity studies have also been done to compute the activation energy (E_a) values from lgσ−1/T Arrhenius plots. A solid state polymeric battery was fabricated by using optimum conducting composition of solid polymer electrolyte (SPE OCC), and some important cell parameters were also calculated from the discharge profile of the cell.

Two kinds of poly(vinyl alcohol) (PVA)-silica composites were prepared with different methods. One composite was prepared by directly mixing PVA with 80 nm silica nano-particles which were made from tetraethoxysilane (TEOS). The another was obtained by the mixing PVA and hydrolyzed TEOS in the presence of acid-catalyst. The properties of the two PVA/silica hybrids were characterized by means of scanning electron microscopy (SEM), UV-Visible spectroscopy, solubility tests, limiting oxygen index (LOI) test, tensile test and dynamical mechanical analysis (DMA), respectively. The results indicate that PVA-TEOS composites (PT for short) display more transparency than PVA-silica nano-particles hybrids (PS for short). At the same time, The PT composites presented more excellent performance than PS in water resistance, fire resistance and mechanical properties. Moreover, the T_g of PT increased with increasing TEOS content, while that of PS decreased.

The intrinsic relationship between molecular chain length and the probability of chain reaction during poly(lactic acid) (PLA) hydrolysis was investigated by Monte Carlo simulation. The chain reaction rate was calculated by introducing a power function of different molecular chain lengths. The hydrolysis of both amorphous and extended-chain crystal PLA was selected as the model system. It is found that, the chain reaction probability was proportional to the chain length with a power of 0.4 for amorphous PLA and 0.7−1 for extended-chain crystal PLA, respectively. These results indicate that PLA with longer chain length usually exhibits larger reaction rate than that with shorter length. Comparing the hydrolysis of the two kinds of PLA, the competition between longer and shorter chains in the different condensed structures is different.

Although addition of β-nucleating agent directly into homo-polypropylene (PPH) is a useful method to improve β-crystal content and toughen PPH, polypropylene random copolymer (PPR) makes this method powerless due to its random structure and low crystallinity. In this study, the β-nucleated PPR with high β-crystal content was prepared by a novel high effective β-nucleating system which consists of β-nucleation agent (TMB-5) and modified zeolite 13X (M13X). It was found that M13X and TMB-5 had a synergistic influence on improving β-crystal content and toughening PPR. The content of β-crystal in PPR/M13X/TMB-5 was significantly larger than the sum of that in PPR/M13X and PPR/TMB-5. Besides, fracture behavior, phase morphology and relaxation of matrix chain segments were also investigated. The results showed that M13X and TMB-5 improved the mobility of amorphous chain segments at low temperature and contributed to much energy dissipation. This work provides a powerful method to modify PPR.

Synthesis and electrochemical polymerization of 9,9-bis(2-(2-(2-methoxy ethoxy)ethoxy)ethyl)-fluorene (EO-F) into poly[9,9-bis(2-(2-(2-methoxy ethoxy)ethoxy)ethyl)-fluorene] (EO-PF) films are reported. The boron trifluoride diethyl etherate electrolyte enables facile preparation of EO-PF films at lower potential compared to LiClO₄/MeCN and the electrochemical polymerizations are discussed. The EO-PF shows good electrochemical behavior and can be dissolved in solvents such as DMSO and THF. The solubility of EO-PF in THF is 2 mg⋅mL⁻¹ and the number average molecular weight is 35300 with a polydispersity index of 1.65. The side chains on C₉ position of the monomer maintain unchanged after electrooxidation into corresponding polymer. The EO-PF dissolved in THF under 365 nm ultraviolet light is sky blue light emitting with the Commission Internationale de L′Eclairage-CIE coordinates of (0.19, 0.15). The electropolymerized EO-PF is used for the first time in chemosensing metal ions, demonstrating fluorescence quenching for Mn²⁺ and Fe³⁺ while fluorescence enhancement for Cr⁶⁺ ions.

By means of dynamic Monte Carlo simulation of bulk lattice polymers in Couette shear flow, it was demonstrated that in addition to velocity gradient the constant driving forces acting as the activation aspect of shear stresses can also raise polymer deformation. Moreover, enhancing driving forces in a flow without any velocity gradient can reproduce non-Newtonian fluid behaviors of long-chain polymers. The simulations of Poiseuille shear flow with a gradient of shear stresses show that, the velocity gradient dominates small deformation in the flow layers of low shear stresses, while the shear stress dominates large deformation in the flow layers of high shear stresses. This result implies that the stress-induced deformation could be mainly responsible for the occurrence of non-Newtonian fluid behaviors of real polymers at high shear rates.