A Unified Thermodynamic Model of Flow-induced Crystallization of Polymer

• Published in: Chinese journal of polymer science Vol. 39; no. 11; pp. 1489 - 1495
• Main Authors: Nie, Cui, Peng, Fan, Xu, Ting-Yu, Sheng, Jun-Fang, Chen, Wei, Li, Liang-Bin
• Format: Journal Article
• Language: English
• Published: Beijing Chinese Chemical Society and Institute of Chemistry, CAS 01.11.2021; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Crystal morphology; Crystal structure; Crystallization; Crystals; Free energy; Hexagonal phase; Industrial Chemistry/Chemical Engineering; Nucleation; Polyethylenes; Polymer Sciences; Polymers; Precursors; Thermodynamic models; Flow-induced chain orientation; Unified thermodynamic model; Flow-induced crystallization
• ISSN: 0256-7679; 1439-6203
• DOI: 10.1007/s10118-021-2622-z

We propose a unified thermodynamic model of flow-induced crystallization of polymer (uFIC), which incorporates not only the conformational entropy reduction but also the contributions of flow-induced chain orientation, the interaction of ordered segments, and the free energy of crystal nucleus and crystal morphology. Specifically, it clarifies the determining parameters of the critical crystal nucleus size, and is able to account for the acceleration of nucleation, the emergence of precursor, different crystal morphologies and structures induced by flow. Based on the nucleation barrier under flow, we analyze at which condition precursor may occur and how flow affects the competition among different crystal forms such as orthorhombic and hexagonal phases of polyethylene. According to the uFIC model, the different crystal morphologies and structures in the flow-temperature space have been clarified, which give a good agreement with experiments of FIC.