Polymerization of Methyl Methacrylate with Bis(Cyclopentadienyl)Titanium Dichloride in a Water-Methanol Mixture: Formation of Tetrahydrofuran-Insoluble Polymer

Methyl methacrylate (MMA) was found to be effectively polymerized with bis(cyclopentadienyl)titanium dichloride (CP2TiCl2) in a water-methanol mixture (1:1, v/v). The polymerization proceeded heterogeneously because the resulting poly(MMA) was insoluble in the system. The rate (R(p)) of the heterogenous polymerization was apparently expressed by R(p) = k[Cp(2)TiCl(2)](2)[MMA](2.5) (at 40 degrees C). The resulting poly(MMA) was observed to consist of tetrahydrofuran (THF)-soluble and insoluble parts. In contrast with the usual radical poly(MMA), the THF-insoluble part was soluble in benzene, toluene, and chloroform but insoluble in polar solvents such as ethyl acetate, acetone, acetonitrile, dimethylformamide, and dimethylsulfoxide. The polymerization was found to be profoundly accelerated by irradiation with a fluorescent room lamp (15 W). The results of copolymerization of MMA and acrylonitrile indicated that the present polymerization proceeds through a radical mechanism.