β-定向结晶聚丙烯无规共聚物的催化合成

Catalytic synthesis of β-crystalline-specified polypropylene random copolymers

将含有β晶成核剂的功能性Ziegler-Natta催化剂用于丙烯/乙烯无规共聚合,制备了一系列具有β-定向结晶功能的β晶型聚丙烯无规共聚物(PPR),采用SEM、FTIR、DSC、偏光显微镜和动态机械热分析方法对PPR进行了表征,研究了PPR树脂的热性能和动态力学性能。实验结果表明,催化剂中的β晶成核剂能够随着聚合过程分散于PPR树脂中,进而在PPR中诱导产生β晶型;聚合物具有良好的类球形颗粒形态;通过成核剂的引入能够在一定程度上提高PPR树脂的模量,但乙烯含量增加引起聚合物结晶能力下降,不利于材料刚性的提高。

A series of β-crystalline-specified polypropylene random copolymers（PPRs） were prepared by using a functional Ziegler-Natta catalyst containing a β-nucleating agent in propylene/ethylene random copolymerization,and the characterization of the PPRs by SEM,FTIR,DSC,polarizing microscopy and dynamic thermomechanic analysis allowed for study on the thermal properties and the dynamic mechanical properties of the PPR resins.The experimental results indicated that the β-nucleating agent in the catalyst could be dispersed in the PPR resins during the polymerization,thus inducing the β-crystal formation.The polymers had excellent spherical-like particle morphology,and with the introduction of the β-nucleating agent,the modulus of the PPR resins could be improved to a certain extent.However the increase of the ethylene content led to the decrease of the crystallizability of the polymers,which was not conducive to the improvement of material rigidity.