两亲性温度及pH敏感性嵌段共聚物PMMA-b-(PAA-co-PNIPAM)的合成与表征  

Preparation and characterization of temperature/pH sensitive amphiphilic block copolymer based on poly(methyl methacrylate)-b-(poly(crylic acid)-b-poly(N-isopropylacrylamide))

作　　者：郭莉[1] 景欢旺[2] 

机构地区：[1]青海大学化工学院,西宁810016 [2]兰州大学化学化工学院功能有机分子化学国家重点实验室,兰州730000

出　　处：《化工新型材料》2012年第4期115-118,137,共5页New Chemical Materials

摘　　要：采用可逆加成断裂链转移自由基聚合方法,成功地制备了两亲嵌段共聚物聚甲基丙烯酸甲酯-b-聚丙烯酸-co-聚异丙基丙烯酰胺(PMMA-b-(PAA-co-PNIPAM)。利用傅立叶红外光谱、核磁共振和透射电镜研究了共聚物的结构特征;用GPC测定了其分子量和分子量分布。透射电镜、激光粒度分析仪和动态光散射结果表明嵌段共聚物在水溶液中能够自组装形成直径为200nm的胶束颗粒。通过紫外-可见分光光度计和差示扫描量热法测得了不同pH值下嵌段共聚物的低临界溶解温度(LCST)。经过接枝后的嵌段共聚物的LCST比PNIPAM要高,且随着pH值的降低,聚合物的LCST随之降低。聚合物的LCST可以通过AA链段与NIPAM链段的比例、温度、pH值来控制。In this paper,poly（methyl methacrylate）-b-（poly（crylic acid）-b-poly（N-isopropylacrylamide））（PMMA-b-（PAA-co-PNIPAM）） which has a core-shell structure with the hydrophobic inner core（PMMA） and the hydrophilic shell（PNIPAM） is prepared by reversible addition-fragmentation transfer（RAFT） radical polymerization.The block copolymer（PMMA-b-（PAA-co-PNIPAM）） comprised PNIPAM as the Thermo-sensitive block and PAA as pH-sensitive block.The products are characterized by FT-IR,1H NMR spectra,TEM and GPC.The copolymers can undergo supramolecular self-assembly to thermo-response nanosized micelles in aqueous media.The sizes of the micelles are determined by transmission electron microscopy（TEM）,granularity analysis and dynamic light scattering instrument（DLS）.The micelles are regularly spherical in shape with an average hydrodynamic diameter around 200 nm.The lower critical solution temperature（LCST） of the copolymer which is higher than PNIPAM is measured by UV-vis and differential scanning calorimetry（DSC）.The LCST is decreased by reducing the pH and which can adjust by changing the ratio of the AA and NIPAAM,temperature and pH.

关 键 词：嵌段共聚物 聚甲基丙烯酸甲酯-b-聚丙烯酸-co-聚异丙基丙烯酰胺 pH-敏感 温度-敏感 

分 类 号：TQ325.7[化学工程—合成树脂塑料工业]