Synthesis of block copolymers by selective H-abstraction and radical coupling reactions using benzophenone/benzhydrol photoinitiating system

Abstract

Block copolymers were synthesized by a simple photochemical strategy based on selective H-abstraction and radical coupling reactions of ketyl macroradicals. Benzophenone (BP) and benzhydrol (Bzh) end functional polymers were synthesized by atom transfer radical polymerization (ATRP) using functional initiators. Subsequently, the resulting end functional polymers were mixed in 1:1 M ratio and irradiated to form ketyl radicals by hydrogen abstraction of the excited BP moieties from Bzh moieties. The influence of various experimental parameters on the polymerization such as type of polymers and solvents were examined. H-1 NMR, UV and GPC measurements clearly pointed out an efficient photoinduced end coupling reaction between ketyl radicals. (C) 2014 Elsevier Ltd. All rights reserved.