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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。
In order to open up the research direction of polylactic acid (PLA) -based functional molecules by direct polycondensation, the polycondensation of PLA-PEG-PLA with self-emulsifying properties was studied using lactic acid and polyethylene glycol (PEG) The ingredients of PLA-PEG-PLA with self-emulsifying properties and the two-stage synthesis process were obtained. The reaction process was followed by mass spectrometry. The structure of the product was characterized by 1 H NMR. The emulsification properties of PLA-PEG-PLA were verified by water dispersion test. The temperature characteristics of the emulsion were also studied. The experimental results showed that PLA-PEG-PLA with stable emulsification ability could be obtained when the feed ratio of lactic acid to PEG1500 was close to 2.57:1. The dilute emulsified system was liquid while the emulsified system with high concentration could be transformed into In a wide temperature range to maintain a stable emulsion gel, changing the ratio of raw materials can be adjusted emulsion characteristics and temperature sensitivity. This study provides a successful case for the synthesis of functional polylactic acid via direct polycondensation.