Molecular Segregation and Melt Memory in Dilute Polycaprolactone with Reduced Entanglements

Ce Shi; Jia-Le Zeng; Ze-Fan Wang; Yong-Feng Men

doi:10.1007/s10118-026-3695-5

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Molecular Segregation and Melt Memory in Dilute Polycaprolactone with Reduced Entanglements

RESEARCH ARTICLE | Updated：2026-08-31

- Molecular Segregation and Melt Memory in Dilute Polycaprolactone with Reduced Entanglements
- Chinese Journal of Polymer Science Vol. 44, Issue 9, Pages: 3104-3118(2026)
- Affiliations：
  
  a.State Key Laboratory of Polymer Science and Technology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
  b.School of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
  c.School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
- Author bio：
  
  zfwang@ciac.ac.cn (Z.F.W.)
  men@ciac.ac.cn (Y.F.M.)
- Funds：
- DOI：10.1007/s10118-026-3695-5
  CLC： [M
- Received：05 March 2026，
  
  Accepted：04 April 2026，
  
  Online First：22 July 2026，
  
  Published：05 September 2026
- Accepted：
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Shi, C.; Zeng, J. L.; Wang, Z. F.; Men, Y. F. Molecular segregation and melt memory in dilute polycaprolactone with reduced entanglements. Chinese J. Polym. Sci. 2026, 44, 3104–3118

Ce Shi, Jia-Le Zeng, Ze-Fan Wang, et al. Molecular Segregation and Melt Memory in Dilute Polycaprolactone with Reduced Entanglements[J]. Chinese Journal of Polymer Science, 2026, 44(9): 3104-3118.
Shi, C.; Zeng, J. L.; Wang, Z. F.; Men, Y. F. Molecular segregation and melt memory in dilute polycaprolactone with reduced entanglements. Chinese J. Polym. Sci. 2026, 44, 3104–3118 DOI： 10.1007/s10118-026-3695-5.

Ce Shi, Jia-Le Zeng, Ze-Fan Wang, et al. Molecular Segregation and Melt Memory in Dilute Polycaprolactone with Reduced Entanglements[J]. Chinese Journal of Polymer Science, 2026, 44(9): 3104-3118. DOI： 10.1007/s10118-026-3695-5.

摘要

This study clarifies that in bimodal polymer mixtures with low entanglement concentrations

the crystallization morphology is strongly related to the molecular weight of the long chains. The lamellar stack structure is determined by the fraction of tie chains. The melt-memory effect has been proven to be related to intrachain interactions rather than entanglements.

Abstract

In polymer processing

low-molecular-weight chemically identical oligomers are typically added to a polymer to improve its processability and mechanical properties by manipulating its entanglement concentration. However

the complicated semi-crystalline morphologies and melt memory effect of less entangled bimodal dispersed mixtures cannot be overlooked. In this study

we systematically examined the crystallization and self-nucleation behavior of poly(

-caprolactone) (PCL) mixtures composed of a relatively

high-molecular-weight (83 kg/mol) fraction and a low-molecular-weight PCL with a mid-chain defect (2 kg/mol). The entanglement concentrations were quantified by linear rheological measurements. Both thermal analysis and small-angle X-ray scattering (SAXS) investigations revealed that pronounced crystallization-induced phase separation (

i.e.

molecular segregation) occurs because of the different nucleation energy barriers. In contrast to our previous investigation using a long chain fraction with a higher molecular weight (200 kg/mol) (

Macromolecules

2024

1632−1641)

the low-molecular-weight oligomer tends to crystallize between adjacent crystalline lamellae composed of long PCL chains due to the lack of intra-crystalline links

for example

entanglements and tie-molecules. The correlation between the melt memory effect and the entanglement concentration was evaluated using self-nucleation experiments. The 2 kg/mol PCL oligomer (with a central defect) did not exhibit melt memory. However

the introduction of high-molecular-weight components

even below the critical entanglement concentration

leads to a wider temperature range

preserving the ordered structure. Our results provide solid evidence that the melt memory effect in polar semi-crystalline polymers originates from the intramolecular interactions of adjacent chain folding rather than entanglements or chain overlaps.

关键词

Keywords

references

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