Application of successive self-nucleation and annealing (SSA) to poly(1-butene) prepared by Ziegler–Natta catalysts with different external donors

Abstract

Alkoxysilane compounds R₁R₂Si(OMe)₂ were used as external donors in 1-butene polymerization with MgCl₂-supported Ziegler–Natta catalysts. The structure of the prepared iPB was characterized by ¹³C NMR and GPC. The thermal properties of poly(1-butene) (iPB) were studied by DSC. The crystallization behavior and sequence length distribution of poly(1-butene) were investigated using successive self-nucleation and annealing (SSA) thermal fractionation technology. The SSA results indicated that steric hindrance of an external donor has more influence on the properties of iPB, as each melting point peak and the enthalpy of fusion of iPB gradually increased with an increase in steric hindrance of the external donor. Considering all properties, cyclopentyl-isopropyl-dimethoxysilane had an advantage compared to other external donors in the polymerization of 1-butene.