聚丙交酯-聚乙二醇-聚丙交酯三嵌段共聚物的合成及其温敏水凝胶性质研究

Synthesis of PLA-PEG-PLA Triblock Copolymer and Property Study of Its Thermo-Sensitive Hydrogel

聚乙二醇（PEG）与丙交酯（LA）在辛酸亚锡催化下共聚，合成了聚丙交酯-聚乙二醇-聚丙交酯三嵌段共聚物（PLA-PEG-PLA），通过核磁共振氢谱（1HNMR）和凝胶渗透色谱（GPC）对其化学结构和分子量进行了表征。该共聚物在化学结构及组成比例适当的条件下，其水溶液在一定浓度时可形成具有温敏效应的水凝胶，通过倒置法测定了共聚物水溶液的溶胶一凝胶转变相图，通过流变仪测定了共聚物水溶液的流变性能。1HNMR和GPC结果表明，该共聚物结构明确，分子量分布较窄；流变性能研究表明，共聚物水溶液流变行为具有温度和频率依赖性。

A triblock copolymer PLA-PEG-PLA was synthesized by copolymerization of PEG and lactide with stannous octoate as catalyst. Its chemical structure and molecular weight were characterized by 1HNMR and GPC. With proper chemical structure and composition, the aqueous solution of this eopolymer at certain concentration could form thermo-sensitive hydrogels. The phase diagram of sol-gel transition for aqueous solu- tion of copolymer was measured by inverting test method. The rheological property was measured using rheme- ter. 1HNMR and GPC results indicated that, the structure of this copolymer was definite and its molecular weight distribution was narrow. Rheological property study showed that the rheological behavior of copolymer aqueous solution had temperature and frequency dependence.