Polymerization of methyl methacrylate by single component catalyst of lanthanocene chloride O(C2H4C5H3CH3)2LnCl (Ln=Y, Nd, Sm)

A novel single component catalyst of lanthanocene chloride O(C2H4C5H3CH3)2LnCl (Ln=Y, Nd, Sm) was used to initiate the polymerization of methyl methacrylate (MMA) in bulk and in toluene solution system. The effects of temperature, time and molar ratio of MMA/Catalyst were studied in detail. The results showed that higher temperature and longer time were favorable for increasing the catalytic activities. Both polymerization conversion of MMA and molecular weight (MW) of PMMA formed in toluene are lower than those from bulk polymerization, which gives Mw as high as 1.52×106, and MMA conversion more than 80%. The syndiotacticity of PMMA prepared at a temperature ranging from 20°C to 80°C is about 65%. GPC (gel permeation chromatography) shows that the MW distribution of PMMA obtained in bulk polymerization is as narrow as 1.3. Kinetic studies indicate that the polymerization rate is a first-order dependence on the concentration of MMA and catalyst, respectively. The overall activation energy of polymerization is 33.9 kJ/mol.