Synthesis of graft copolymers onto styrenic polymer backbone via "grafting from" raft process

A new synthetic methodology is developed for preparing graft copolymers via RAFT polymerization method by the "R group approach" onto styrenic polymers. In this approach, latent sites of the styrenic polymer was brominated first and then converted into macro-RAFT agents with pyrazole and thio dodecyl as the Z groups. This was used to synthesize graft copolymer such as polystyrene-graft-polymethyl methacrylate (PS-g-PMMA), polystyrene-graft- poly(isobornyl acrylate), polystyrene-graft-poly[2-(acetoacetoxy)ethyl methacrylate] (PS-g-PAEMA), and poly(para-methoxystyrene)-graft-polystyrene (P(p-MS)-g-PS). The polymers are characterized by gel permeation chromatography, 1H NMR, IR, and atomic force microscopy (AFM). The morphology of PS-g-PMMA in THF was investigated using AFM and island-like features were noticed. The AFM studies of the PS-g-PAEMA graft copolymers revealed the formation of globules and ribbon-like morphological features. The PS-g-PAEMA graft copolymers form complex with Fe(III) in dimethylformamide and the AFM studies suggest the formation of globular superstructures. Copyright © 2012 Wiley Periodicals, Inc.