Synthesis and characterization of a brush type graft copolymer via RAFT and "click" chemistry methods

In this study, well-known poly(4-vinylbenzyl- g -ethylene glycol) [P(4-VB- g -EG)] brush type graft copolymer was synthesized by recycling additive/fragmentation chain transfer (RAFT) polymerization and a "click" chemistry method. In the first step, a RAFT agent (CTA) was synthesized for this purpose by the reaction of 2-(2-chloro ethoxy) ethanol and potassium ethyl xanthogenate salt. In the second step, poly(4-vinylbenzyl chloride) [P(4-VBC)] was synthesized by performing RAFT polymerization of 4-vinylbenzyl chloride using a RAFT initiator. In the third step, poly(4-vinylbenzyl-N 3 ) [P(4-VB-N 3 )] was produced by a reaction that synthesized P(4-VBC)] and NaN 3 . In addition, PEG-propargyl (alkyne-terminated-PEG) was obtained by the reaction between polyethylene glycol (PEG-3000) and propargyl chloride. In the last step, poly(4-VB- g -EG) brush type graft copolymer was obtained by the reaction of PEG-propargyl and poly(4-VB-N 3 ) via the "click" chemistry method. The synthesized products were characterized utilizing various spectroscopic methods. The DSC result showed that the glass transition temperature value of the brush type graft copolymer was 30 °C, different from that of the homopolymer. The SEM analysis demonstrated that the surface morphology of the homopolymer and brush type graft copolymers differed. The fact that the brush type graft copolymer has two different decomposition temperatures such as 220 °C and 410 °C has been proven by TGA analysis.