One‐step synthesis of block‐graft copolymers via simultaneous reversible‐addition fragmentation chain transfer and ring‐opening polymerization using a novel macroinitiator

Abstract

ABSTRACT One‐step synthesis of block‐graft copolymers by reversible addition‐fragmentation chain transfer (RAFT) and ring‐opening polymerization (ROP) by using a novel initiator was reported. Block‐graft copolymers were synthesized in one‐step by simultaneous RAFT polymerization of n ‐butylmethacrylate ( n BMA) and ROP of ε‐caprolacton (CL) in the presence of a novel macroinitiator (RAFT‐ROP agent). For this purpose, first epichlorohydrin (EPCH) was polymerized by using H 2 SO 4 via cationic ring‐opening mechanism. And then a novel RAFT‐ROP agent was synthesized by the reaction of potassium ethyl xanthogenate and polyepichlorohydrin (poly‐EPCH). By using the RAFT‐ROP agent, poly[CL‐b‐EPCH‐b‐CL‐(g‐ n BMA)] block‐graft copolymers were synthesized. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the one‐step polymerization reaction were evaluated. The block lengths of the block‐graft copolymers were calculated by using 1 H‐nuclear magnetic resonance ( 1 H NMR) spectrum. The block length could be adjusted by varying the monomer and initiator concentrations. The characterization of the products was achieved using 1 H NMR, Fourier‐transform infrared spectroscopy, gel‐permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, elemental analysis, and fractional precipitation ( γ ) techniques. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2651–2659