Synthesis of Block Copolymers Based on N-alkyl Substituted Acrylamide via Combination of Reversible Addition-Fragmentation Transfer Polymerization and Click Chemistry

Abstract

Chain transfer agents of azido terminated trithiocarbonate and alkyne terminated trithiocarbonate were synthesized by esterification reaction with trithiocarbonate (2-dodecylsulfanylthiocarbonylsulfanyl-2-methylpropionic acid, DMP). The kinetics of reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAAm) with the above three kinds of thiocarbonate as RAFT agents showed that chain transfer activity of azido-DMP and alkyne-DMP was similar, which was lower than that of DMP. Homopolymer (poly(N,N-dimethylacrylamide) (PDMA-C ≡ CH)) and block copolymer (P(DMA-b-NIPAAm)-N3) were successfully prepared by RAFT polymerization with desired structure. The subsequent preparation of triblock P(DMA-b-NIPAAm-b-DMA) was carried out by the click reaction. The molecular weight of P(DMA-b-NIPAAm-b-DMA) was the summation of molecular weight of reactant polymers and the molecular weight distribution was small (PDI<1.15), proving the successful click reaction.