【摘要】 为了开辟通过直接缩聚法合成聚乳酸(PLA)基功能分子的研究方向,以乳酸和聚乙二醇(PEG)为原料,对具有自乳化特性的PLA-PEG-PLA的缩聚合成进行了研究,得出了具有自乳化特性的PLA-PEG-PLA的配料条件及两阶段合成工艺。通过质量测定对反应过程进行了跟踪,通过1 H NMR对产物的结构进行了表征,通过水分散实验验证了PLA-PEG-PLA乳化特性,并研究了乳化体系的温度特性。实验结果表明,乳酸与PEG1500的投料比在接近2.57∶1时可以得到具有稳定乳化能力的PLA-PEG-PLA,浓度稀的乳化体系为液态,而浓度高的乳化体系经过低温处理后可以转变为在较宽的温度范围内保持稳定的乳化凝胶,改变原料配比可以调节乳化特性及温敏性。本研究为通过直接缩聚法合成功能性聚乳酸提供了成功案例。更多还原

【Abstract】 In order to open up such a research direction that poly(lactic acid)(PLA)based functional molecules were synthesized by direct polycondensation synthesis,the synthesis of PLA-PEG-PLA obtained with a self-emulsifying properties were studied with lactic acid and poly(ethylene glycol)(PEG)as raw material.Ingredients conditions and a two-stage synthesis process were determined through experiments.Mass method was used to track reaction process,1 H NMR was used to characterize product’s structure,and water dispersion experiments were used to verificate the emulsifying properties.Otherwise,temperature characteristics of the emulsion was also studied.The experimental results showed that PLAPEG-PLA with stable emulsification ability can be obtained when feed ratio of lactic acid to PEG1500was close to 2.57∶ 1.Dilute emulsion system was liquid but concentrated emulsion systems can be changed to a stable emulsion gel after a cold treatment.Emulsifying properties and temperature sensitivity can be changed by changing raw materials ratio.This study laid the foundation for synthesizing functional poly(lactic acid)by direct polycondensation.更多还原