Journal of Applied Polymer Science, Vol.74, No.5, 1293-1297, 1999
Kinetics for copolymerization of methyl methacrylate with N-cyclohexylmaleimide
The kinetics for the radical copolymerization of methyl methacrylate (MMA) with N-cyclohexylmaleimide (NCMI) was investigated. The initial copolymerization rate R-p is proportional to the initiator concentration to the power of 0.54. The apparent activation energy of the overall copolymerization was measured to be 69.0 kJ/mol. The monomer reactivity ratios were determined to be r(NCMI) = 0.42 and r(MMA) = 1.63. R-p reduces slightly, and the molecular weight of the resultant copolymer decreases with increasing the concentration of the chain transfer agent N-dodecanethiol (RSH). The more the transfer agent, the narrower the molecular weight distribution of the resulting copolymer. The following chain-transfer constant of RSH far the copolymerization of MMA with NCMI in benzene at 50 degrees C was obtained: C-s = 0.23. The glass transition temperature (T-g) of the copolymer increases with increasing f(NCMI), which indicates that adding NCMI can improve the heat resistance of Plexiglas.