AB_3型超支化聚合物/聚丙烯共混体系等温结晶动力学

Isothermal crystallization kinetics of AB_3 hyperbranched polymer(HBP)/polypropylene(PP) blends

利用示差扫描量热仪(DSC)研究了等规聚丙烯/5%AB3型超支化聚合物共混体系的等温结晶动力学,分别讨论了不同分子质量的超支化聚合物对聚丙烯结晶行为的影响,结果表明,共混物的结晶速度明显高于纯聚丙烯样品,且随着超支化聚合物分子质量的增加,结晶速度增加。但当超支化聚合物分子质量比较高时,结晶速度反而有所降低。偏光显微镜照片显示,超支化聚合物的引入使体系晶核数目急剧增加,球晶的半径明显变小。

In this paper,the isothermal crystallization kinetics of pure isotactic polypropylene(iPP) and iPP with 5% AB3 hyperbranched polymer(HBP) added is investigated by differential scanning calorimetry(DSC).During isothermal crystallization,the crystallization rate of the blends is higher than those of iPP remarkably.Moreover,the value of t1/2 becomes smaller with increasing the HBP molecular weight in blends,however,the crystallization rate of the blend decreases when the higher molecular weight HBP(n=12 500) is added.The crystallization rate of the blends is more sensitive to temperature than that of iPP.The polarized micrographs of the HBP/PP blend show the number of effective nuclei increases obviously and the sphereulite size reduces rapidly.