Polymerization and Sequence Structure Characterization of High Ethylene-Content Ethylene-Propylene Elastomers

Ethylene-propylene elastomers(EPR) of high ethylene content were synthesized with a homogeneous vanadium-based catalyst. The effect of high ethylene contents (70 mol % in the gas phase) and ethyl trichloroacetate (ETCA) promoter on the copolymerization of ethylene propylene was investigated. The effect of ethylene sequence structure on the property of copolymer was also examined. The polymers synthesized were characterized by ¹³C-NMR , gel permeation chromatography, Fourier transform infrared spectroscopy, and X-ray diffraction. The results showed that the ETCA promoter is an effective gel inhibitor in ethylene propylene copolymerization with high ethylene concentration. Ethylene block index (EB) obtained using ¹³C-NMR analysis was a good characterization parameter to reflect the property of copolymer. The resulting polymers showed good physical properties compared to a commercial product.