Formation of poly(methyl methacrylate) with novel solubility characters in the photopolymerization with bis(cyclopentadienyl)titanium dichloride in a water–methanol mixture

Methyl methacrylate (MMA) was observed to be easily polymerized in the photopolymerization with bis(cyclopentadienyl)titanium dichloride (Cp₂TiCl₂) in a water–methanol mixture under irradiation of a 15-W fluorescent room lamp. The polymerization proceeded heterogeneously. The rate (R_p) of heterogeneous photopolymerization in a 1 : 1 (v/v) water–methanol mixture at 40°C was apparently given by R_p=k[Cp₂TiCl₂]^0.2 [MMA]^2.4. The resulting poly(MMA) was found to contain a tetrahydrofuran (THF)-insoluble part. The separated THF-insoluble part differed significantly from the usual radical poly(MMA) in solubility characters. It is of great interest that the THF-insoluble poly(MMA) was soluble in benzene and toluene, but insoluble in polar solvents, such as ethyl acetate, acetone, methyl ethyl ketone, dimethylformamide, and dimethylsulfoxide. The copolymerization results of MMA and acrylonitrile revealed that the present photopolymerization initiated with Cp₂TiCl₂ proceeds via a radical mechanism. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 525–531, 1998