无规和嵌段聚丙烯酸酯类温敏共聚物的转变行为研究

Study on transformation behavior of random and block polyacrylate thermosensitive copolymers

以2-甲基-2-丙烯酸-2-(2-甲氧基乙氧基)乙酯(MEO_2MA)和聚乙二醇甲醚甲基丙烯酸酯(OEGMA_(300))为单体,以1∶1的比例采用原子转移自由基聚合(Atom transfer radical polymerization,ATRP)法合成分子量分布较窄的温敏无规共聚物(P(MEO_2MA-co-OEGMA_(300)))和嵌段共聚物(P(MEO_2MA-b-OEGMA_(300)))。利用核磁共振氢谱(H1 NMR)、凝胶渗透色谱仪(GPC)表征其结构;通过紫外-可见光分光光度计(UV-Vis)分析聚合物在水溶液中的转变行为;采用白光干涉仪测试位于硅基底表面的温敏高分子薄膜的膜厚随温度的变化和薄膜的温敏性能。结果表明:具有不同链结构的温敏聚合物的转变行为存在显著的差异,P(MEO_2MA-co-OEGMA_(300))仅具有单一的低临界溶解温度(Lower critical solution temperature,LCST),而P(MEO_2MA-b-OEGMA_(300))则显示出两个LCST;P(MEO_2MA-coOEGMA_(300))和P(MEO_2MA-b-OEGMA_(300))在薄膜中均表现出更宽的温度转变区间。

2-(2-methoxyethoxy)ethoxyethyl methacrylate(MEO 2MA)and Poly(ethylene glycol)methyl ether methacrylate(OEGMA 300)with a molar ratio of 1∶1 were applied as monomers to synthesize random copolymer poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-poly(ethylene glycol)methyl ether methacrylate)and block copolymer poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-block-poly(ethylene glycol)methyl ether methacrylate)by applying atom transfer radical polymerization(ATRP).The copolymers had narrow molecular weight distribution.1H NMR and GPC were applied to characterize their structure.UV-Vis spectroscopy was used to investigate the transition behaviors in aqueous solution.White light interferometry was used to test the change of thermo-responsive polymer film located on the surface of silicon substrate in film thickness with the temperature and thermosensitivity of the film.The results show that,the transition behaviors of thermo-responsive polymers with different chain structure have significant differences.P(MEO 2MA-co-OEGMA 300)only has single Lower critical solution temperature(LCST),while P(MEO 2MA-b-OEGMA 300)shows LCST;P(MEO 2MA-co-OEGMA 300)and P(MEO 2MA-b-OEGMA 300)present wider temperature transformation internal in the film.