Influence of Silane-Type Electron Donors on Ziegler–Natta Catalysts in Ethylene Polymerization and Ethylene/α-Olefin Copolymerization

Abstract

This study examines the influence of silane-type electron donors on the performance of Ziegler–Natta (ZN) catalysts in ethylene polymerization and ethylene/α-olefin copolymerization. Three electron donors, dicyclopentyl dimethoxysilane (D donor), dipiperidyl dimethoxysilane (DPPDMS), and dipyrrolidinyl dimethoxysilane (DPRDMS), were investigated. The presence of electron donors generally reduces catalytic activity in both homo- and copolymerization, with aminosilanes (DPPDMS and DPRDMS) causing a more pronounced decrease than D donor due to their stronger coordination with Ti active sites. The addition of electron donors also increases polymer molecular weight while narrowing molecular weight distribution, particularly in ethylene/1-butene copolymerization. Although comonomer incorporation remains low regardless of donor type, the resulting copolymers exhibit a more uniform chemical composition distribution compared to those synthesized without electron donors. Notably, polymers produced with D donor display a narrower molecular weight distribution than those obtained with aminosilane donors. These findings should provide valuable insights into the role of silane-type electron donors in tuning copolymer properties and contribute to the advancement of ZN catalysis in copolymerization.