Synthesis of graft copolymer by ATRP of MMA from poly(phenylacetylene)

The present report describes the synthesis of a densely grafted copolymer consisting of a rigid main chain and flexible side chains by the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) from an ATRP initiator‐bearing poly(phenylacetylene) poly(BrPA)]. Poly(BrPA) was obtained by the polymerization of 4‐ethynylbenzyl‐2‐bromoisobutyrate using Rh(NBD)Cl]₂ in the presence of Et₃N. The ¹H NMR spectrum showed that poly(BrPA) was in the cis‐transoid form. Upon heating at 30 °C for 24 h the cis‐transoid form was maintained. ATRP of MMA from the poly(BrPA) was carried out at 30 °C using CuX (X = Br, Cl) as the catalyst and N,N,N′,N′,N′‐pentamethyldiethylenetriamine as the ligand, and the resulting graft copolymers were investigated with ¹H NMR and SEC. To analyze the graft structure in more detail, the graft copolymers were hydrolyzed with KOH and the resultant poly(MMA) part was investigated with ¹H NMR and SEC. The polydispersity indexes of 1.25–1.45 indicated that the graft copolymers have well‐controlled side chains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6697–6707, 2006