Studies on binary copolymerization and glass transition temperatures of methyl methacrylate with ethyl methacrylate and n ‐butyl methacrylate

In this article, bulk copolymerization of methyl methacrylate (MMA) with ethyl methacrylate (EMA) and n ‐butyl methacrylate ( n ‐BMA) was carried out at 60°C. The monomer reactivity ratios obtained by nonlinear fitting with Mayo‐Lewis equation were as follows: r MMA = 0.93 ± 0.03, r EMA = 0.96 ± 0.03 for the MMA/EMA, and r MMA = 0.99 ± 0.05, r n ‐BMA = 1.11 ± 0.06 for the MMA/ n ‐BMA series. A new equation proposed in view of bond rotation flexibility (Liu et al., J Phys Chem B 2008, 112, 93), which contains mole fractions of triads and T g 's of corresponding periodic copolymers, was applied to describe the relation of T g 's of MMA‐EMA, MMA‐ n ‐BMA copolymers with their compositions and sequence distribution. Excellent fitting results were obtained and T g values of the assumed periodic copolymers were predicted by fitting the random copolymers. The influence of the substituent volume as well as substituent density on the T g of poly(methyl methacrylate) (PMMA) was also tentatively predicted.