基于酶引发的温敏聚合物的合成与性能

Synthesis and properties of temperature-sensitive polymers based on enzyme initiation

以2-甲基-2-丙烯酸-2-(2-甲氧基乙氧基)乙酯(MEO2MA)和低聚乙二醇甲醚甲基丙烯酸酯(OEGMA500)为单体,利用辣根过氧化物酶(HRP)/乙酰丙酮(ACAC)/H2O2三元催化体系引发自由基聚合,合成了温敏无规共聚物P(MEO2MA-co-OEGMA500)。通过GPC、1HNMR、FTIR、DSC等对合成聚合物的数均分子量、分子量分布、结构及热性能进行了表征。通过测定聚合物溶液在不同温度下的透光率和粒径对聚合物的温敏性能进行了表征。制备了n(MEO2MA)∶n(OEGMA500)分别为100∶0、95∶5、93∶7、90∶10、85∶15的温敏聚合物。结果表明,随着单体OEGMA500投料占比的增加,合成聚合物的低临界溶解温度(LCST)从24℃增加至39℃,聚合物玻璃化转变温度(Tg)从–11.75℃逐渐降低至–14.74℃;LCST随聚合物水溶液浓度增加而降低;升高温度,聚合物平均粒径增加,比低温条件下聚合物平均粒径大82.5~135.6 nm。

Temperature-sensitive random copolymers,P(MEO2 MA-co-OEGMA500)were synthesized by free radical polymerization from 2-(2-methoxyethoxy)ethyl methacrylate(MEO2 MA)and polyethylene glycol methyl ether methacrylate(OEGMA500)using horse radish peroxidase(HRP)/acetylacetone(ACAC)/H2 O2 as initiator system.The number-average molecular weight,molecular weight distribution,structure and thermal properties of the synthesized copolymers were characterized by GPC,1 HNMR,FTIR and DSC.The temperature-sensitive properties of the copolymers were evaluated by determining light transmission and particle size of polymer aqueous solution at different temperatures.Temperature-sensitive copolymers with n(MEO2 MA)∶n(OEGMA500)of 100∶0,95∶5,93∶7,90∶10,and 85∶15 were synthesized.The results showed that the lower critical solution temperature(LCST)of the synthetic copolymers increased from 24℃to 39℃,and the glass-transition temperature(Tg)gradually decreased from–11.75℃to–14.74℃with the increase of feed proportion of OEGMA500.The LCST decreased with the increase of concentration of copolymer aqueous solution.With increasing temperature,the average particle size of the copolymer increased,which was 82.5~135.6 nm larger than that at low temperature.