无规共聚PP与嵌段共聚PP共混的研究

Study on Blending of Random Copolymerized Polypropylene and Block Copolymerized Polypropylene

用IR、DSC、SEM和力学性能测试方法研究了一种无规共聚PP(PP -R)和一种嵌段共聚PP(PP -B)及其共混物的结构与性能。结果表明 ,PP -R和PP -B都能结晶 ,但PP -R结晶较慢、结晶度较低 ;PP -R不含而PP -B含有呈球粒状分散的乙丙橡胶 (EPR)相和乙烯嵌段 (PE)相 ;随共混物中PP -B含量增加 ,常温和低温冲击韧性显著提高 ,力学强度在略有下降后能持平或回升 ,这些性能变化是上述PP -R、PP -B结构特点的一种综合效应。

Structure and properties of random copolymerized polypropylene(PP-R) and block copolymerized polypropylene(PP-B) and their blends are studied by IR,DSC,SEM and mechanical property testing.Results show that PP-R and PP-B are crystallizable,but the crystallization rate and crystallinity of PP-R are slower and lower than that of PP-B.PP-R does not contain ethylene-propylene rubber(EPR) phase dispersed in the form of spherical particles and ethylene block(PE) phase,but PP-B does.With the increase of PP-B contents,impact toughness of the blends at room temperature and low temperature increases evidently and mechanical strength can hold constant or increase again after decreasing slightly.These changes of blend property can be regarded as a combined effect of the structure characteristics mentioned above.