PCL-PEG2000-PCL的水溶液溶解状态变化温度曲线

Temperature Curves of Dissolving State Changes of PCL-PEG2000-PCL in Pure Water

目的考察聚ε-己内酯-聚乙二醇2000-聚ε-己内酯的水溶液状态变化温度曲线形态。方法以两端羟基的聚乙二醇2000引发ε-己内酯开环聚合,通过对物料添加量的控制,得到不同ε-己内酯聚合度的三嵌段共聚物。将系列聚合度的共聚物置于纯水中搅拌分散并逐渐升温,记录溶解和析出时的温度并做相图。结果得到了聚ε-己内酯片段分别约为500、1000、2000 Da的三嵌段共聚物,水溶液状态变化温度曲线发现随着温度的升高,聚ε-己内酯片段聚合度的增高,其溶解温度逐渐升高,其析出温度逐渐降低,即系列浓度下,其溶解相窗口逐渐变窄。结论合成的系列聚ε-己内酯-聚乙二醇2000-聚ε-己内酯嵌段共聚物水溶液具有特殊的、有规律的温度-形态相图,值得进一步研究和开发。

Objective To investigate temperature curves of state changes of polyε-caprolactone-poly ethylene glycol-polyε-caprolactone in pure water.Methods Tri-block copolymer were obtained by using poly ethylene glycol 2000 with two hydroxyl group both on the ends to initiate ring-opening polymerization reaction ofε-caprolactone.And the degree of polymerization ofε-caprolactone was modified by the additive amount of the substance.Copolymers with a series of degrees of polymerization were mixed within pure water by stirring and increasing the temperature.The dissolving temperature and precipitation temperature were recorded and the phase diagram was drawn.Results Tri-block copolymer with polyε-caprolactone segments of about 500,1000,2000 Da,respectively,was obtained.It was discovered in the temperature curves of state changes in pure water that with the increase of the temperature and the degree of polymerization,the dissolving temperature gradually increased,and the precipitation temperature gradually decreased.Namely,the dissolved phase window became narrower and narrower with series concentration.Conclusion Synthesized polyε-caprolactone-poly ethylene glycol-polyε-caprolactoneblock copolymer has special and regular temperature-morphology phase diagram,worth further study and development.