Abstract: Four-armed star-shaped copolymer of methyl methacrylate(MMA)/ N-cyclohexylmaleimide(NCMI) with heat-resistance was synthesized by atom transfer radical copolymerization with the CuBr/bpy catalyst in anisole, initiated by tetra(bromomethyl)benzene. Alinear plot of ln([M]₀/[M]) versus reaction time was obtained by using anisole as solvent. In contrast, the use of cyclohexanone as solvent results in that the rate of copolymerization decreases as the reaction proceeds. Using anisole as the solvent in the copolymerization, the molecular weight of the resultant copolymer(measured by triple detection SEC) increased linearly with the increase of conversion, and the molecular weight distributions are narrow. The glass transition temperature of the resultant copolymer was higher than that of the pure PMMA. The synthesized four-armed star copolymer was used as macroinitiator for the cationic polymerization of 2-methyl-2-oxazoline to yield star shaped poly(MMA-co- NCMI)/poly(2-methyl-2-oxazoline) block copolymers. The approximately linear increase of the molecular weight with the increase of reaction time and the low molecular weight distribution demonstrate a controlled chain extension reaction.

Key words: "Living"controlled polymerization, N-Cyclohexylmaleimide, Heat-resistance, 2-Methyl-2-oxazoline, Star-shaped copolymer