Origin of High Elastic Recovery of Hard-elastic Polypropylene Film at Room Temperature: the Mixed Contribution of Energy Elasticity and Entropy Elasticity

作     者：Jia-Yi Xie Rui-Jie Xu Cai-Hong Lei Jia-Yi Xie;Rui-Jie Xu;Cai-Hong Lei

作者机构：Guangdong Provincial Key Laboratory of Functional Soft Condensed MatterGuangdong Provincial Engineering Laboratory of Energy Storage Materials and DevicesSchool of Materials and EnergyGuangdong University of TechnologyGuangzhou 510006China 

出 版 物：《Chinese Journal of Polymer Science》 (高分子科学（英文版）)

年 卷 期：2020年第38卷第12期

页      面：1325-1334页

核心收录：

学科分类：07[理学] 0817[工学-化学工程与技术] 08[工学] 070205[理学-凝聚态物理] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China(Nos.51773044 and 51603047) Research and Development Plan for Key Areas in Guangdong Province(No.2019B090914002) Guangdong Province Science and Technology Plan Project(No.2016A010103030) the PhD Start-up Fund of Natural Science Foundation of Guangdong Province,China(No.2016A030310344) 

主　　题：Hard-elastic material Elastic recovery Entropy elasticity Energy elasticity 

摘      要：The crystalline and amorphous regions were alternately arranged in the hard elastic polypropylene(PP)films with row-nucleated *** this work,their structure evolution during stretching and recovery at room temperature was followed and the elastic recovery mechanism was discussed by twice cyclic tensile *** the first stretching to 100%,the lamellae crystals are parallel separated and the intercrystallite crazing is formed at the first yield *** nano-cavities within the intercrystallite crazing appear when the strain reaches 20%.The strain-hardening process accompanies with the lamellae long period increasing and the intercrystallite crazing *** the secondary yield point,the lamellae cluster is further separated and more nano-cavities *** first and second recovery processes are complete *** recovery,firstly,the energy elasticity provided by nano-cavities surface tension drives the shrinkage of material,and then the entropy elasticity related to amorphous chain relaxation plays a leading role when the strain is smaller than the secondary yield *** elastic recovery process of hard elastic material is the co-contribution of energy elasticity and entropy *** work gives a clearer recognition about the source of hard elastic property and the role of amorphous region in material s deformation.