BENZIL N,N-DIMETHYLAMINOETHYL METHACRYLATE SYSTEM AS PHOTOINITIATOR FOR METHYL-METHACRYLATE POLYMERIZATION/

Photopolymerization of MMA in bulk and an air atmosphere at 20 degrees C was studied using the benzil/N,N-dimethylaminoethyl methacrylate (D MAEMA) combination as photoinitiator. The polymerization rate (R(p)) w as proportional to the 0.3 power of the benzil concentration and the 0 .6 power of the DMAEMA concentration. R, reaches a maximum and then de clines as either the benzil concentration is increased (>0.03 M) or th e DMAEMA concentration is increased (>0.01 M). The termination of poly merizatin was found to be bimolecular. DMAEMA can also act as a chain transfer agent; its chain transfer constant was evaluated to be 0.093. The methacrylate moiety of DMAEMA can participate in the polymerizati on process and cause crosslinking.