NON-ISOTHERMAL CRYSTALLIZATION OF POLY(L-LACTIDE)(PLLA) UNDER QUIESCENT AND STEADY SHEAR CONDITIONS  

作　　者：李忠明 

机构地区：[1]College of Polymer Science and Engineering,State Key Laboratory of Polymer Materials Engineering, Sichuan University

出　　处：《Chinese Journal of Polymer Science》2010年第3期357-366,共10页高分子科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.50527301)

摘　　要：The non-isothermal crystallization of poly（L-lactide） （PLLA） under quiescent and steady shear flow conditions was in situ investigated by using polarizing optical microscopy （POM） with a hot shear stage and wide-angle X-ray diffraction （WAXD）. The shear rate and the cooling rate both play a significant role in the final crystalline morphology and crystallinity. Under quiescent conditions, the morphology assumes different sized spherulites, and its crystallinity dramatically reduces with increasing the cooling rate. On the other hand, the shear flow increases the onset crystallization temperature, and enhances the final crystallinity. When the shear rate is above 5 s^-1, cylindrite-like crystals are observed, furthermore, their content depends on the cooling rate.The non-isothermal crystallization of poly（L-lactide） （PLLA） under quiescent and steady shear flow conditions was in situ investigated by using polarizing optical microscopy （POM） with a hot shear stage and wide-angle X-ray diffraction （WAXD）. The shear rate and the cooling rate both play a significant role in the final crystalline morphology and crystallinity. Under quiescent conditions, the morphology assumes different sized spherulites, and its crystallinity dramatically reduces with increasing the cooling rate. On the other hand, the shear flow increases the onset crystallization temperature, and enhances the final crystallinity. When the shear rate is above 5 s^-1, cylindrite-like crystals are observed, furthermore, their content depends on the cooling rate.

关 键 词：Poly（L-lactide） （PLLA） Non-isothermal crystallization SHEAR Cylindrite-like crystal 

分 类 号：O631.31[理学—高分子化学]