Influence of shear on polypropylene crystallization kinetics
Influence of shear on polypropylene crystallization kinetics
复制标题
DOI：
10.1140/epje/i2004-10046-8
复制
发表时间：
2004-10
期刊：
影响因子：
--
通讯作者：
H. Huo;Y. Meng;Hong-fei Li;Shichun Jiang;L. An
中科院分区：
文献类型：
--
作者：
H. Huo;Y. Meng;Hong-fei Li;Shichun Jiang;L. An
用光学显微镜研究了异丙基聚丙烯熔体在剪切作用下的等温结晶动力学。从200 ℃到结晶温度的剪切对动力学有增强作用，但仅在200 ℃下剪切时，剪切效应不明显。实验结果表明，松弛在结晶过程中起着重要作用，球晶生长速率随剪切速率的增大而增大，并受松弛控制。流动对结晶动力学的影响可以通过考虑流动结果导致的有序度的增加是熔体自由能的有效变化来理解。采用Laurizen-Hoffman理论和DE-IAA模型对iPP剪切结晶动力学进行了较好的描述。
Isothermal crystallization kinetics under shear in the melt of iPP was investigated by optical microscopy. It appears that shearing from 200 to the crystallization temperatures enhanced the kinetics, but the shear effect was not obvious if the melt of iPP was sheared only at 200. The experiment results show that relaxation plays an important role during crystallization, and that spherulite growth rates increased with shear rates and were governed by relaxation. The effect of flow on the crystallization kinetics can be understood by considering that the increase of the degree of order due to flow results is an effective change of the melt free energy. The Laurizen-Hoffman theory and the DE-IAA model were used to describe the shear-induced crystallization kinetics of iPP excellently.