中文摘要：

采用超临界二氧化碳（scCO2）沉淀聚合法,在不添加高分子表面活性剂及共溶剂的前提下,以AIBN为引发剂,二乙二醇二甲基丙烯酸酯为交联剂,成功制备了交联的聚（N-异丙基丙烯酰胺）温度敏感型微凝胶;通过扫描电镜（SEM）、差示扫描量热分析（DSC）等方法对聚合物的微观形貌进行了表征,测定了微凝胶的相转变温度,同时也考察了样品在无水乙醇中的溶胀度。实验结果表明,在优化反应条件下,可以得到分散的、粒径约为2.0μm的干燥粉末;单体转化率大于90%;不同组成结构样品的相转变温度（VPTT）在15℃～30℃范围;且微凝胶在无水乙醇中有良好的溶胀性能。

英文摘要：

The use of supercritical carbon dioxide（scCO2） as an alternative to traditional aqueous and organic solvents has attracted much attention in the fields of extraction,polymer synthesis and materials processing,etc.The white,dry,fine powders were obtained directly from cross-linking polymerization of N-isopropylacrylamide（NIPAm） in scCO2 with diethyleneglycoldimethylacrylate（DEGDMA） as cross-linker.The effects of the reaction pressure,the initial concentration of initiator,cross-linker on the yield and morphology of the resulted polymer were systematically investigated.The thermo-responsive microgels were characterized by scanning electron microscopy（SEM）,differential scanning calorimetry（DSC）,and the equilibrium swelling ratio（SR）.The monomer conversion is increased with cross-linker ratio.Under higher cross-linker ratios the cross-linked PNIPAm particles with 2.0 μm diameters are generated in scCO2 at higher yields.The volume phase transition temperatures（VPTTs） of the microgels are 15 ℃～30 ℃.The microgels have better swelling behavior in pure ethanol.