Facile synthesis of highly pure block copolymers by combination of RAFT polymerization, click reaction and de-grafting process
作者：Guangdong Zhao, Peipei Zhang, Chengbo Zhang and Youliang Zhao*
關鍵字：suprapure block copolymer, RAFT polymerization, click chemistry, graft reaction, hybrid material
論文來源：期刊
具體來源：Polymer Chemistry, 2012, DOI: 10.1039/C1PY00396H
發表時間：2012年
pubs.rsc.org/en/content/articlelanding/2012/py/c1py00396h
A facile strategy to synthesize highly pure block copolymers with polymeric segments such as polystyrene, polyacrylamides and polyacrylates was described. The methodology involves grafting reaction by tandem RAFT polymerization and azide-alkyne cycloaddition reaction and a subsequent de-grafting reaction via aminolysis or radical-induced addition-fragmentation reaction. S-methoxycarbonylphenylmethyl S’-propynyloxycarbonylethyltrithiocarbonate was used to synthesize Z-alkyne-functionalized macro chain transfer agents, and silica particles grafted with well-defined “living” block copolymers were obtained by simultaneous RAFT process and click reaction using clickable RAFT agents and azido-functionalized silica particles as raw materials. This approach afforded grafted polymers with polydispersity typically lower than 1.2 and silica-polymer hybrids with grafting density in the range of 0.020-0.091 chains nm-2 as the grafted chains had molecular weights between 4920 and 26300 g mol-1. Highly pure block copolymers with terminal functionalities such as thiol, methyldithio, carboxyl, hydroxyl and halogen were obtained by de-grafting process and postmodification, and azido-functionalized silica particles were efficiently recovered. The cycles comprising grafting and de-grafting reactions could be applied for many times, and no significant decrease in grafting density was noted, indicating the versatility and generality of this approach for surface modification, synthesis of high-purity block copolymers and recycle of clickable solid substrate.