论文部分内容阅读
Two multi-nuclear titanium complexes [Ti(η5-Cp*)Cl(μ-O)]3 (1) and [(η5-Cp*TiCl)(μ-O)2(η5-Cp*Ti)2(μ-O)(μ-O)2]2Ti (Cp*=C5Me5) (2) have been investigated as the precatalysts for syndiospecific polymerization of styrene. In the presence of modified methylaluminoxane (MMAO) as a cocatalyst, complexes 1 and 2 display much higher catalytic activities towards styrene polymerization, and produce the higher molecular weight polystyrenes with higher syndiotacticities and melting temperatures (Tm) than the mother complex Cp*TiCl3 does when the polymerization temperature is above 70℃and the Al/Ti molar ratio is in the low range especially.
Two multi-nuclear titanium complexes [Ti (η5-Cp *) Cl (μ-O)] 3 (1) and [η5-Cp * TiCl) (Μ-O) 2] 2Ti (Cp * = C5Me5) (2) have been investigated as the precatalysts for syndiospecific polymerization of styrene. In the presence of modified methylaluminoxane (MMAO) as a cocatalyst, complexes 1 and 2 display much higher catalytic activities towards styrene polymerization, and produce the higher molecular weight polystyrenes with higher syndiotacticities and melting temperatures (Tm) than the mother complex Cp * TiCl3 does when the polymerization temperature is above 70 ° C and the Al / Ti molar ratio is in the low range especially.