文献类型：期刊文献

中文题名：等规聚丙烯加工过程中的降解机理及性能变化

英文题名：Degradation Mechanism and Mechanical Properties Change of Isotactic Polypropylene in Processing

作者：孟鑫[1];辛忠[1];蔡智[2]

机构：[1]华东理工大学联合化学反应工程研究所,上海200237;[2]中国石油化工股份有限公司九江分公司,江西九江332004

年份：2006

卷号：35

期号：5

起止页码：444

中文期刊名：石油化工

外文期刊名：Petrochemical Technology

收录：CSTPCD;;EI(收录号：20064210188053);Scopus;北大核心:【北大核心2004】；CSCD:【CSCD2011_2012】；

基金：2005年中国石油化工集团股份有限公司资助项目(205100)

语种：中文

中文关键词：等规聚丙烯;熔体流动指数;多分散指数;降解;结晶;力学性能

外文关键词：isotactic polypropylene; melt flow index ; polydispersity index ; degradation; crystallization; mechanical property

摘要：研究了等规聚丙烯(iPP)在加工过程中的降解机理及其力学性能的变化。采用熔体流动指数测定仪、红外光谱法对加工过程中iPP的相对分子质量及其分布、降解所产生的功能基团浓度的变化进行了表征;对iPP的结晶、熔融及力学性能进行了测试。实验结果表明,iPP在挤出过程中相对分子质量减小,相对分子质量分布变窄;随熔体流动指数(MFI)的增加,iPP结晶峰的峰温向高温方向移动,其移动趋势随多分散指数(PDI)的稳定逐渐减弱;结晶速率加快,其加快速率也随PDI的稳定逐渐减弱。MFI对iPP力学性能的影响主要体现在冲击强度和断裂伸长率上,冲击强度随MFI的增大而减小;断裂伸长率随MFI的增大而增大,达到极大值后减小。
Degradation mechanism of isotactic polypropylene （iPP） in processing was studied by multiple extrusions. Relative molecular mass of iPP and its distribution were characterized by means of melt flow index（MFI）and polydispersity index（PDI）. Concentration of functional group generated in degradation was measured by means of FFIR. Disproporfionation of alkyl radicals during processing caused scission of macromolecule chains and formation of C = C double bound, and led to decrease of relative molecular mass. Crystallization and melting characteristics of iPP were investigated by means of differential scanning calorimetry. Increase of peak temperature of crystallization was due to production of smaller molecules of iPP in degradation. Decrease of PDI enhanced regularity of iPP and led to increase of peak temperature of crystallization. Mechanical properties of iPP in processing, especially impact strength and elongation at break, were related to MFI and PDI. Impact strength became smaller with increase of MFI ,but elongation at break kept max value within experimental range of MFI and PDI.