Synthesis of graft copolymer with pendant macrocycles via combination of ATRP and click chemistry

Graft copolymers with pendant macrocycles were synthesized via " graft onto" method. First, cyclic polystyrene (PS) was achieved by the combination of atom transfer radical polymerization (ATRP) and Cu-catalyzed azideealkyne cycloaddition (CuAAc), and then an alkynyl group was introduced to cyclic PS. Meanwhile, poly(3-azide-2-hydroxypropyl methacrylate) (PGMA-N-3) was synthesized by ATRP of glycidyl methacrylate (GMA) and successive ring-opening of pendant epoxide ring with NaN3. The graft copolymer was achieved by the following click reaction between PGMA-N-3 and alkynyl-containing cyclic PS. GPC and H-1 NMR were utilized to characterize the obtained graft copolymers, and a maximal grafting density of 20% was observed. Thermal behaviors of linear PS, cyclic PS and PGMA grafted with cyclic PS (PGMA-g-cPS) were investigated by differential scanning calorimeter (DSC), and T-g of PGMA-g-cPS is higher than those of linear and cyclic PS. (C) 2015 Elsevier Ltd. All rights reserved.