Synthesis And Thermo-Sensitive Property Of Cyclic-Pnipam Polymer By Atom Transfer Radical Polymerization(ATRP) And Click Chemistry

Well-defined cyclic-PNIPAM polymer was synthesized by a combination of atom transfer radical polymerization (ATRP) and click chemistry, and the kinetics of the polymerization as well as the thermo-sensitive property of the polymer were studied in detail.The atom transfer radical polymerization of NIPAM was performed in a sealed system filled with nitrogen at 25℃,using ABMP prepared by the reaction of propargyl alcohol and 2-bromoisobutyrlbromide as initiator, HMTETA/CuBr, PEDETA/CuBr, Me6TREN/CuBr as the catalyst system as well as iso-propyl alcohol and water(v/v,16/1) as solvent.The study of the kinetics revealed the linearity plot of the Mn,GPC against conversion and the reaction time.The study of the thermo-sensitive property showed that the LCST of the polymer was highed to 39.8℃,compared to that of PNIPAM(about 32℃).Then cyclic-PNIPAM polyme was synthesized by click chemistry.The study of the thermo-sensitive property showed that the LCST of cyclic-PNIPAM was lowered to 34.8℃,compared to linear-PNIPAM-Br(about 39.8℃).