Syndiospecific polymerization of styrene over silica supported CpTiCl(3) catalysts

Abstract

An homogeneous CpTiCl(3) catalyst and two types of silica-supported CpTiCl(3) catalysts (CpTiCl(3)/SiO2 and CpTiCl(3)/MAO/SiO2) were used to investigate the catalytic behavior for styrene polymerization. Among these, the CpTiCl(3)/SiO2 catalyst showed the highest catalytic activity and syndiotacticity in styrene polymerization. From an electron spin resonance (ESR) study, it is suggested that the CpTiCl(3)/SiO2 catalyst is easily activated for styrene polymerization through interaction with MAO as a cocatalyst. The intensities of ESR signals with g values of 1.984 and 1.980 were found to be well correlated with polymerization activity. The CpTiCl(3)/SiO2 catalyst was more stable than the homogeneous CpTiCl(3) catalyst.