中文摘要：

将N-异丙基丙烯酰胺（NIPAm）与具有温敏性的大分子单体进行共聚，制得了主链与支链在水溶液中具有不同相转变温度的温敏支化聚合物。经过双重相转变过程后，通过扫描电子显微镜（sEM）可以观察到聚合物链形成的具有较大比表面积的“葡萄串”结构，光散射实验中聚合物粒径大小随着温度升高发生两次突变进一步解释了双重相转变过程中聚合物微观形态的变化。在温敏支化聚合物溶液样品的差示扫描量热法（DSC）曲线中可以观察到35℃与21℃出现两组相对独立的吸热峰，从热力学的角度描述了双重相转变行为。通过使用二维红外相关光谱技术分析了温敏支化聚合物各基团对温度扰动的响应顺序，其结果说明仅存在于支链中的丙烯酸丁酯（BA）结构单元要先于NIPAm结构单元发生变化，对双重相转变行为的机理有了更进一步的说明。“葡萄串”结构的形成有效地提高了温敏聚合物的疏水比表面积，有望应用于生化分离领域。

英文摘要：

Thermo-responsive branch copolymer was prepared via copolymerization with Nisopropylacrylamide （NIPAm） and the thermo-responsive macromonomer. The main chain and branch chain of thermo-responsive branch copolyrner performed two different phase transition temperatures in aqueous solution. After dual-phase-transition, ＂grape cluster＂ morphology with large specific surface area could be observed by SEM. There were two break points in light scattering curves, which further explained the dual-phase-transition process in morphology. Two relatively independent endothermic peaks could be observed at 35℃ and 21℃ in DSC curves of the thermo-responsive branch copolymer sample, which described the dual-phase-transition process from the viewpoint of thermodynamics. The order of groups changing induced by temperature was investigated by 2D-IR spectroscopy. The result confirmed that the BA unit, which only existed in the branch chains, changed prior to the NIPAm units. The ＂grape cluster＂ morphology effectively increased the specific surface area of thermoresponsive polymer, which might be potentially applied in bioseparation.