Hyperbranched polystyrene-linear polystyrene-hyperbranched poly(methyl methacrylate) triblock polymer (HPS-b-LPS-b-HPMMA) was synthesized by following steps: First of all, two kinds of trithiocarbonates with a alkynyl group or bromide atom (ATC and BTC) were synthesized. Then reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene (St) was carried out to obtain linear polystyrene macro-RAFT agents with terminal alkynyl group and bromine. Bromine end of the macro-RAFT agent was replaced by azide group. Then, in the presence of the macro-RAFT agents, self-condensing atom transfer radical copolymerization (SCATRCP) of St/CMS or MMA/BPPM was carried out to obtain hyperbranched PSt-linear PSt (HPS-b-LPS) with terminal alkynyl group and hyperbranched PMMA-linear PSt (HPMMA-b-LPS) with terminal azido group. Finally, two kinds of diblock copolymer were coupled by click reaction to get hyperbranched-linear-hyperbranched triblock polymer (HPS-b-LPS-b-HPMMA). ¹H NMR, GPC results showed that the final polymer with the controlled molecular weight and the expected structure was obtained.

Key words: reversible addition-fragmentation chain transfer (RAFT), click reaction, hyperbranched polymer, block polymer