立构缺陷分布均匀性对等规聚丙烯/玻璃纤维复合材料结晶及形态的影响

利用具有不同立构缺陷分布均匀性的聚丙烯,制备了玻璃纤维/聚丙烯(简称玻纤/PP)复合材料,研究了玻纤含量和PP立构缺陷分布对复合材料的结晶动力学行为、结晶结构及聚集态结构的影响。结果表明,立构缺陷分布更不均匀的PP-A具有比PP-B拥有更高的结晶能力、结晶速率和更低的结晶活化能(ΔE)。玻纤的加入促进了PP的结晶,但在相同的玻纤加入量时,PP-A的结晶能力始终比PP-B更强,说明立构缺陷分布的均匀性比玻纤的加入对结晶影响更大;玻纤的加入更倾向于促进立构缺陷分布不均匀的PP-B形成β晶,且在相同条件下,在PP-B中的分散更加均匀。上述结果表明,在玻纤/PP复合材料的结构与性能设计中,PP立构缺陷分布的均匀性也是需要重视的重要因素。

Effects of Stereo-Defect Distribution on the Crystallization Behavior and Morphology of Isotactic Polypropylene/Glass Fiber Composites

Using iPP resins with similar molecular weight and distribution but different uniformities of stereodefect distribution,the glass fiber/iPP composites were prepared,so as to investigate the role of stereo-defect distribution of PP on the crystallization kinetics,crystalline structure and morphology of the composites.The results reveal that PP-A with uniform of stereo-defect distribution possesses stronger crystallizability,higher crystallization rate and lower activation energy.The addition of glass fiber increases the crystallization of PP,however,after addition of the same amount of glass fiber,PP-A always exhibits stronger crystallizability,suggesting that stereodefect distribution is the most important factor in determining the crystallizability of the composites,compared with addition of glass fibers.Moreover,the addition of glass fiber favors the formation of β-phase in PP-B with more uniform stereo-defect distribution,which also disperse more uniformly in PP-B.The results above indicate that in the structure-properties design of PP/glass fiber composites,the uniformity of stereo-defect distribution is a very important factor which must be taken into consideration.