Interplay between Macroscopic Stretching and Microscopic Phase Transition Revealed in Butene-1/1,5-Hexadiene Random Copolymers

• DOI: 10.1021/acs.macromol.9b02463
• Publication Date: 2020-03-10T18:08:53Z
• Authors: Wei Li; Long Liu; Lirong Zheng; Yahui Lou; Zhe Ma; Yuesheng Li
• Keywords: 02 engineering and technology; 0210 nano-technology

The intrinsic coupling effect between the multiscale microstructure and macroscopic performance is a fundamental issue in polymer engineering physics. Combing tensile testing situ wide-angle X-ray diffraction, stretching-induced polymorphic transformation from tetragonal form II into hexagonal I butene-1/1,5-hexadiene random copolymers was studied this work. mechanical response crystallite evolution of designed with various co-unit concentrations were combined to reveal interplay stretching microscopic phase transition for whole deformation process. results show that elastic does not change structure significantly it yield triggers II–I transition, which happens at comparable strain around 0.06 all polymers studied. It indicated destroys skeleton bears external region generation new tie chains enhances stress transfer lamellae, triggering transition. more transformed improves strength, increased also required ensure proceeding A direct correspondence established kinetics true course Furthermore, after increases modulus molecular network by 2 orders magnitude respect original II. This indicates acts as physical cross-links enhancement hardening strongly dependent on crystal modification.