聚氨酯微球的接枝改性及温敏特性  

Grafting Modification and Thermosensitive Properties of Polyurethane Microspheres

作　　者：龚梅[1] 张利[2] 黄棣[2] 杜晶晶[2] 周名兵[2] 李玉宝[2] 解慧琪[1] 

机构地区：[1]四川大学华西临床医学院,生物治疗国家重点实验室,干细胞与组织工程研究室,成都610041 [2]四川大学纳米生物材料研究中心,分析测试中心,成都610064

出　　处：《高等学校化学学报》2014年第8期1843-1848,共6页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:50903052);中国博士后基金(批准号:2013M53197)资助~~

摘　　要：以N-异丙基丙烯酰胺(NIPAAm)为单体,二苯甲酮(BP)为光敏剂,过硫酸胺(APS)为自由基引发剂,采用溶液中光接枝方法制备了具有温度敏感特性的聚氨酯微球(PUS).傅里叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)结果表明,在聚氨酯微球表面形成了聚异丙基丙烯酰胺(PNIPAAm)接枝聚合物层.在接枝过程中,延长反应时间与增加引发剂浓度均有利于提高接枝率.常温下,接枝率随反应时间延长呈线性增长,当反应时间超过40 min后,接枝率基本保持稳定;而引发剂浓度对接枝率的影响存在最佳优化值,即其浓度为单体质量分数的3%.采用差示扫描量热法(DSC)对接枝改性前后聚氨酯微球的温敏特性进行分析表征,证实改性后的微球在35℃左右出现低临界互溶温度(LCST),在此温度附近表现出对温度敏感特性.接触角测试与溶胀测试结果表明,在低临界互熔温度以下,接枝改性的聚氨酯微球具有良好的亲水性.Surface modification of polyurethane microspheres（ PUS） by grafting poly（ N-isopropylacrylamide） （ PNIPAAm） was initiated under UV light. Besides benzophenone（ BP） was used as a photosensitizer, ammo-niumperoxydisulfate（ APS） was used as a free radical initiator. The occurrence of grafting copolymerization of PNIPAAm was testified by the attenuated total multiple reflection technique（ ATR-IR） . Scanning electron mi-crograph（ SEM） showed that the surface morphology of PUS changed significantlyafter modification. The lower critical solution temperature（LCST） of the PUS was determined by differential scanning calorimetry（DSC）, and the wettability of the membrane assembled by PU microspheres was investigated by water contact angle measurement. The results showed that the grafting yield increased with irradiation time and finally reached the saturation value. As the concentration of APS initiator was increased, the grafting yield had a maximum. In addition, the modified PU microspheres were thermosensitive similar to that of PNIPAAm gel, and the LCST was determined about 35 ℃. The water contact angle measurement proved that the PNIPAAm-g-PU micro-spheres demonstrated good hydrophilic behavior below the LCST.

关 键 词：聚氨酯微球 聚异丙基丙烯酰胺 温敏性 接枝聚合 

分 类 号：O631[理学—高分子化学]