Strain-induced Stereocomplex Formation from the Initially Amorphous Poly(L-lactic acid)/Poly(D-lactic acid) Samples  

作　　者：Tao Liao Zhi-yong Jiang Yong-feng Men 

机构地区：[1]State Key Laboratory of Polymer Physics and Chemistry&Key Laboratory of Polymer Science and Technology,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China

出　　处：《Chinese Journal of Polymer Science》2025年第4期655-665,共11页高分子科学(英文版)

基　　金：finicially supported by the National Natural Science Foundation of China (No. 52103047)。

摘　　要：The strain-induced crystallization behaviors of ultrasonic micro-injection molded poly(L-lactic acid)/poly(D-lactic acid)(PLLA/PDLA)samples from an amorphous state were investigated by stress-strain relations and in situ wide angle X-ray diffraction(WAXD) measurements.The formation of direct strain-induced stereocomplex(SC) was evident.In samples molded at 50 and 80 °C,this phenomenon can be attributed to the acceleration of the ordered structures due to the existence of a large number of SC nuclei.The SC nuclei are assumed to serve as the transient physical cross-links to initiate the strain-induced crystallization.The onset of strain-induced crystallization is analogous to the heating induced structural reorganization.Consequently,the observed strain-induced SC process can be considered a pseudo process,which is actually thermally induced.Upon further stretching,the actual strain-induced crystallization occurs with the exclusive formation of the homocrystallite(HC),while the preceding formed SC crystals undergo slight fragmentation during subsequent tensile deformation.At 120 °C,due to the reduced number of SC nuclei within the sample,the occurrence of cold crystallization during stretching plays a more significant role than SC nuclei with respect to the strain-induced SC process,as demonstrated by in situ WAXD measurements upon annealing in both the static and stretched states.

关 键 词：Amorphous PLLA/PDLA blend Strain-induced crystallization Strain-induced SC formation 

分 类 号：O631[理学—高分子化学]