Radical copolymerization between methyl methacrylate andN-cyclohexylmaleimide with thiol as an inifer

N-dodecanethiol (RSH) was found efficient to initiate the radical copolymerization of methyl methacrylate (MMA) with N-cyclohexylmaleimide (NCMI) at 40–60°C. The initial copolymerization rate, Rp, increases respectively with increasing [RSH] and the mol fraction of NCMI in the comonomer feed, fNCMI. The molecular weight of the copolymer decreases with increasing [RSH]. The initiator transfer constant of RSH was determined to be CI = 0.21. The apparent activation energy of the overall copolymerization was measured to be 46.9 kJ/mol. The monomer reactivity ratios were determined to be rNCMI = 0.32 and rMMA = 1.35. The glass transition temperature of the copolymer increases obviously with increasing fNCMI, which indicates that adding NCMI may improve the heat resistance of plexiglass.