Shear effects on crystalline structures of poly(L-lactide)
Shear effects on crystalline structures of poly(L-lactide)
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DOI：
10.1039/c3ce40466h
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发表时间：
2013-09
期刊：
影响因子：
3.1
通讯作者：
Peitao Xiao;Hong-fei Li;Shaoyong Huang;H. Wen;Donghong Yu;Yingrui Shang;Jingqing Li;Zhonghua Wu-Zhonghu
中科院分区：
文献类型：
--
作者：
Peitao Xiao;Hong-fei Li;Shaoyong Huang;H. Wen;Donghong Yu;Yingrui Shang;Jingqing Li;Zhonghua Wu-Zhonghu
采用小角X射线散射（SAXS）和广角X射线衍射（WAXD）研究了剪切作用对聚L-乳酸（PLLA）最终结晶结构的影响。WAXD结果表明剪切对PLLA的晶体结构没有影响。小角X射线散射结果表明，在垂直于剪切方向时，随着剪切速率的增大，晶体层片的长周期和厚度均增大，而在平行于剪切方向时，晶体层片的长周期和厚度基本不变。研究了不同剪切温度和相同剪切应变不同剪切速率下制备的样品的结构变化。结果表明，在不同剪切条件下，聚合物熔体的中间相和剪切作用对有序相的影响是影响PLLA晶体结构的关键因素。
The shearing effects of sheared polymer melts on their finally formed crystalline structures of poly(L-lactide) (PLLA) were investigated by means of small angle X-ray scattering (SAXS) and wide angle X-ray diffraction (WAXD). The results of WAXD prove that shear has no effects on the crystal structure of PLLA. The SAXS results demonstrate that both of the long period and the thickness of crystalline lamellae increase with rising shear rates when vertical to the shear direction, but remains constant when being parallel to the shear direction. The structural changes for samples prepared with different shear temperature or under the same shear strain but different shear rate were investigated. The mesophase of polymer melts and shearing effects on their pre-ordered phase turned out to be the key factor affecting the crystal structure of PLLA under different shearing conditions.