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

Abstract

A two-armed macroinitiator was prepared by acylation of OH groups in poly[styrene-co-p-bis(2-dihydroxyethyl)amino methyl styrene] with alpha-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 degrees C. All the polymers were structurally characterized by FTIR and H-1 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 degrees C and 210 degrees C, were less thermally stable than poly(styrene) (Ti approximate to 330 degrees C) or poly(isobornylacrylate) (Ti approximate to 255 degrees C). The graft copolymers showed a lower glass-transition temperature than the macroinitiator and poly(isobornylacrylate). The dielectric constants (epsilon) of all the polymers were measured at 1 kHz at room temperature. (C) 2008 Elsevier Ltd. All rights reserved.