Synthesis and characterization of two-armed graft copolymers prepared with acrylate and methacrylate using atom transfer radical polymerization

A two-armed macroinitiator was prepared by acylation of OH groups in poly[styrene-co-p-bis(2-dihydroxyethyl)amino methyl styrene] with α-bromoisobutyryl bromide. A series of grafting studies with isobornylacrylate was carried out in the presence of the macroinitiator and the catalyst CuBr/2,2′-bipyridyne(bpy) at 110 °C. All the polymers were structurally characterized by FTIR and 1H NMR spectra. During the 20 h grafting reaction, the number-average molecular weight of the macroinitiator increased from 68,600 to 162,900 and the polydispersity decreased from 2.15 to 1.52 all the graft copolymers, which had initial decomposition temperatures between 192 °C and 210 °C, were less thermally stable than poly(styrene) (Ti ≈ 330 °C) or poly(isobornylacrylate) (Ti ≈ 255 °C). The graft copolymers showed a lower glass-transition temperature than the macroinitiator and poly(isobornylacrylate). The dielectric constants (ε) of all the polymers were measured at 1 kHz at room temperature.