核壳结构PNIPAM温敏类凝胶的自组装及性能研究

Synthesis of a novel thermosensitive core-shell polymer microspheres and their application

采用无皂乳液聚合法合成了一种以聚苯乙烯为核,聚(N-异丙基丙烯酰胺-co-N-丙烯酸琥珀酰亚胺酯)为壳的单分散核壳结构聚合物微球。利用FT-IR、SEM、TEM和粒度分析对制备样品的物相结构、形貌进行了测试表征。表征结果显示聚合物具有良好的单分散性和清晰的核壳结构,且聚合物微球具有良好的温敏性,其低临界转变温度(LCST)为31℃。进而考察了微球与菠萝蛋白酶的结合率,研究了微球所含琥珀酰亚胺酯基与菠萝蛋白酶上伯氨基的反应活性,结果表明在pH值=6.39,t=4℃时,微球与菠萝蛋白酶的结合率最高,且在4h内已经基本进行完全。

In this article,core-shell microspheres were synthesized by surfactant-free emulsion polymerization and seed polymerization with polystyrene as the core and poly（N-isopropylacrylamide-co-acryloxysuccinimide）as the shell by modified emulsifier-free emulsion polymerization.The structures and properties of the composite were characterized by FT-IR,SEM,TEM and particle size analyzer.The results show that the as-prepared materials exhibited a well monodispersity and clear core-shell structure.The relationship of diameter and temperature was detected,and the result showed that the microspheres have thermo-sensitive property with the lower critical solution temperature（LCST）about 31℃.The bromelain was covalently conjugated to the surface of the microsphere through the reaction between primary amino groups and the succinimide ester groups in the shell due to their high reactivity.The influence of pH and temperature on binding rate of the two substances were investigated.It was found that the optimum conditions were pH=6.39,t=4 ℃,and the binding rate reach the maximum in 4h.