Photopolymerization of methyl methacrylate using dye-sensitized semiconductor based photocatalyst

Photopolymerization of methyl methacrylate (MMA) was carried out using semiconductor (CdS) as a photocatalyst under visible light exposure. The influences of additives like eosin (dye) and triethylamine on the photochemical properties of semiconductor (CdS) particle and photopolymerization of MMA were studied. A 2-3% conversion was achieved on using only CdS as photocatalyst. On using an electron donor (Et3N) along with CdS however a conversion of up to 14% was reached. The molecular weight in this case however was low. On carrying with eosin dye along with CdS, up to 22% yield of the polymer was obtained. The polymer so obtained was characterized by GPC. Polydispersity was found to be in the range of 6-6.5 for the polymer obtained by using dye as sensitized semiconductor catalyst and 4-4.5 for the polymer obtained using only dye as catalyst. The free radical polymerization of MMA has been established with EPR spectra.