Stereospecific radical polymerization of methacrylate bearing oxazolidone structure and improvement of glass transition temperature of urethane methacrylate copolymers

Abstract

We synthesized the novel methacrylate monomer bearing an oxazolidone structure (M1) and performed radical polymerization of M1 by traditional procedures. The glass transition temperature (T_g) of the obtained polymer (P1) was a significantly high value compared to that of poly(methyl methacrylate) and typical poly(urethane methacrylate)s. The copolymers of M1 and monofunctional urethane methacrylate derived from 2-hydroxyethyl methacrylate and phenyl isocyanate (M2) exhibited a linear rise of the T_g values depending on the composition ratio of M1. The NMR analysis and the estimation of monomer reactivity ratio and Q–e values suggested that the improvement of glass transition temperature resulted from a stereoregularity, meaning a syndiotacticity of the copolymers improved with increasing the composition ratio of M1. Furthermore, the thermal curing reaction of M1 or M2 with bifunctional urethane acrylate successfully proceeded, then the T_g value of the cured product from M1 was much higher than that from M2.