【摘要】 合成了不同嵌段的可降解的温敏型聚乙交酯丙交酯-聚乙二醇-聚乙交酯丙交酯共聚物(DL-lactide-co-glycolide-b-ethyleneglycol-b-DL-lactide-co-glycolide,PLGA-PEG-PLGA)。用红外、核磁共振、凝胶渗透色谱等表征了其化学结构、分子量及分子量分布,研究了其相变过程。用辐照法成功地进行了PLGA-PEG-PLGA分子量调整。实验结果表明,在反应温度150℃催化剂辛酸亚锡0.04g反应8h,5.08g乙交酯与12.61g丙交酯(摩尔比为1∶2)的条件下,产物溶于水后得到的水凝胶具有明显的相变过程。不同分子量的共聚物相变温度不同,在固定聚乙二醇分子量且共聚物溶液浓度相同条件下,共聚物中丙交酯与乙交酯比例越高,共聚物分子量越大,相同浓度下的分子量越大的共聚物形成的溶胶-凝胶转变温度越低,凝胶-溶胶转变温度越高。当辐照20kGy样品的分子量分布最大,从而改变凝胶的相变温度。更多还原

【Abstract】 PLGA-PEG-PLGA triblock copolymer were synthesised with different compositions. Structure and molecular weight of the copolymer were characterized by FTIR, 1H-NMR and GPC. Phase diagram of the copolymer and their molecular weight variation under E-beam irradiation were studied. The results showed gelation of the co- polymer synthesized in 8h at 150℃ with 0.04g catalyst, 5.08g glycolide, and 12.61g DL-lactide (molar ratio 1:2) had sharp sol-gel phase transition. In an aqueous solution of defined concentration of the copolymer with PEG of fixed molecular weight, by increaseing the DLLA/LA ratio and molecular weight of the copolymer, the temperature of sol-gel phase transition decreased, while the temperature of gel-sol phase transition increased. Maximum polydisper- sity could be achieved by irradiating the copolymer to 20kGy.更多还原