抗冲共聚聚丙烯的结晶与相形态

用POM、DSC、WAXD、DMA、AFM对两种乙烯含量、相对分子量及其分布、橡胶相含量几乎完全相同的、韧性差异很大的抗冲共聚聚丙烯(IPC)的结晶、相形态进行了研究.实验结果表明,两者的结晶形态、结晶行为相似.相比IPC-B,IPC-A中分散相和基体的相容性较好.IPC基体、分散相的组成分析发现,分散相的外层为软的乙丙无规共聚物(EPR),内部为硬的聚乙烯(PE)晶区,构成一种复杂的包藏结构.IPC的增韧效果主要来自于相形态和分散状况的贡献.提出了IPC的相结构模型,以描述IPC多相体系的相结构及两种IPC中E-b-P的作用与差异.

CRYSTALLIZATION AND PHASE MORPHOLOGY OF IMPACT POLYPROPYLENE COPOLYMERS

Crystal morphology,internal structure of dispersed phase and phase morphology for two impact polypropylene copolymers with the same ethylene content,rubber content,relative molecular weight and relative molecular weight distribution,but obviously different toughness were investigated by polarized optical microscope,differential scanning calorimetry,wide angle X-ray diffraction,dynamic mechanical analysis and atomic force microscope.It was found that the crystallization morphology and behavior of both samples were similar,but the compatibility between the dispersed phase and the matrix in IPC-A was better than that in IPC-B.Moreover,phase composition of the matrix and the dispersed phase of the different IPC were analyzed.It was found that the dispese phase displayed a complex concealment structure.Models of phase structure were proposed to describe the phase structure of both IPC heterophase systems and the action of Eb-P in the IPC.It is suggested that phase morphology plays a more important role as a compatibilizer in enhancing impact strength of IPC.