Effects of Molecular Weight and Chain Structure of Ethylene?propylene Block Copolymers on Structure and Performance of PP/EPR Blends

doi:10.19491/j.issn.1001-9278.2020.01.005

Abstract

Abstract: A series of ethylene?propylene block copolymers (EP) with different molecular weights and average sequence length of ethylene monomer units were designed and synthesized by using slurry polymerization process and then used as a compatibilizer for polypropylene (PP)/ethylene?propylene rubber (EPR) blends. The effects of the content and molecular weight of block copolymer on the performance and the evolution of dispersed phase of the blends were investigated. The results indicated that there was an optimum content of EP for compatibilization in the PP/EPR blending system. The addition of EP in a small amount could efficiently control the size and morphology of dispersed phase and therefore enhanced the impact strength of the blends significantly. Meanwhile, the higher molecular weight for EP was beneficial to the impact performance of the blends. The similarity in the composition of EP and EPR was crucial to the compatibilization effect for PP/EPR blends.

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