Thermal polymerization and photopolymerization of ethyl methacrylate with bis(cyclopentadienyl)titanium dichloride in a water–methanol mixture: Formation of a polymer with novel solubility characters

Methacrylate monomers such as methyl methacrylate, ethyl methacrylate (EMA), phenyl methacrylate, and benzyl methacrylate were found to be heterogeneously polymerized in high yields with bis(cyclopentadienyl)titanium dichloride (Cp 2 TiCl 2 ) at 40°C in a 1:1 (v/v) water–methanol mixture under irradiation of a 15‐W fluorescent room lamp. The polymerization of EMA with Cp 2 TiCl 2 in a 1:1 (v/v) water–methanol mixture also proceeded at a moderate rate in the dark. The polymerization behavior of EMA with Cp 2 TiCl 2 in a water–methanol mixture was examined under various conditions, both in the dark and under irradiation. The resulting poly(EMA) was observed to contain a considerable part that was acetone insoluble. In contrast to the usual radical poly(EMA), the fractionated acetone‐insoluble part was insoluble in tetrahydrofuran, chloroform, ethyl acetate, methyl ethyl ketone, acetonitrile, dimethyl sulfoxide, and dimethylformamide, though it was soluble in aromatic solvents such as benzene and toluene. We prepared a bilayer film (48.7 μm) consisting of one acetone insoluble layer and one acetone‐soluble layer. The film was observed to bend toward side of the acetone‐insoluble layer in a 1:1 (v/v) water–acetone mixture. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 166–175, 2001