含PLA-PEG-PLA三嵌段共聚物的 可降解聚氨酯的合成及表征

用聚乙二醇（PEG）和左旋丙交酯（L－LA）合成了不同比例的聚乳酸－聚乙二醇三嵌段共聚物（PLA-PEG-PLA），通过傅立叶变换红外光谱分析（FTIR）和核磁共振(1H NMR)测试分析了所得嵌段共聚物的结构。并以此嵌段共聚物为软段，用溶液法和六亚甲基二异氰酸酯（HDI）和扩链剂（BDO）以不同的比例合成了一系列聚氨酯,通过傅立叶变换红外光谱分析（FTIR）和差动量热扫描分析（DSC）表征聚氨酯结构。对此聚氨酯在37 ℃的PBS缓冲溶液（pH＝7.4）中进行模拟体内环境的降解测试，通过失重率来评价聚氨酯的降解速率，结果表明降解速度与软硬段比例，共聚物中PEG/PLA的比例有关。并且实验表明此材料不会引起红细胞发生溶血。因此这种新型可降解聚氨酯材料可以根据各组分以及组分比例来调整聚合物的降解速率，此材料将在组织工程支架以及药物缓释载体领域有广阔的应用前景。

Synthesis and Characterization of Biodegradable Polyurethane Containing PLA-PEG-PLA Block Copolymers

The tri-block copolymer(polylactide-poly(ethylene glycol)-polylactide,PLA-PEG-PLA) were synthesized.The structures of the tri-block copolymer were analyzed by Fourier transform infrared(FTIR) and nuclear magnetic resonance spectroscopy(1H-NMR).A series of polyurethane,which have different component ratios of PLA-PEG-PLA,1,6-hexamethylene diisocyanate(HDI) and 1,4-butanediol(BDO),were synthesized by solution polymerization.FTIR and differential scanning calorimetry(DSC) were used to study the properties of the series of polyurethane.The degrees of degradation were investigated by exposing these PUs to the PBS buffer solution.With the increase of the ratios of soft/hard segment and PEG / PLA,the rates of mass loss enhance.The PLA-PEG-PLA-polyurethane can not make red cells hemolysis.These polyurethanes may be useful for a wide range of applications.