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以环氧丙烷聚醚三元醇(PPO)为起始剂,开环聚合D型丙交酯(DLA),合成三臂环氧丙烷聚醚三元醇-聚右旋乳酸(PPO-PDLA)嵌段预聚体.采用端基活化技术对预聚体进行端羟基活化,再与L型丙交酯(LLA)进行逐步开环聚合,合成了不同分子量的三臂环氧丙烷聚醚三元醇-聚右旋乳酸-聚左旋乳酸(PPO-PDLA-PLLA)嵌段共聚物.采用红外(FTIR)、核磁(NMR)和凝胶渗透色谱(GPC)等对三臂PPO-PDLA-PLLA嵌段共聚物的测试表明,合成的嵌段共聚物分子链具有很高的立构规整度;通过调节LLA单体与PPO-PDLA预聚体的投料比,不仅可控制产物的分子序列结构,而且样品的数均分子量可大于100 kDa.差示扫描量热仪(DSC)和广角X射线衍射(WAXD)结果显示,三臂PPO-PDLA-PLLA嵌段共聚物的异构体链段分子间生成立构复合晶体,其熔点约为200℃,且没有PLLA均聚物链段结晶现象.实验结果表明,这是一类具有实际应用价值的新型耐热聚乳酸(PLA)材料.
Polylactic acid (PPO-PDLA) was synthesized by ring-opening polymerization of D-lactide (DLA) with propylene oxide polyether triol (PPO) Block prepolymer was prepared by end-group activation technique, and then the terminal hydroxyl groups of the prepolymer were activated. Then the ring-opening polymerization was carried out with L-lactide (LLA) to synthesize three-arm propylene oxide polyether ternary (PPO-PDLA-PLLA) block copolymer was synthesized by the method of FTIR, NMR and gel permeation chromatography (GPC) The test of the segment copolymer shows that the molecular chain of the synthesized block copolymer has a high stereoregularity. By adjusting the feed ratio of the LLA monomer and the PPO-PDLA prepolymer, not only the molecular structure of the product can be controlled, The number average molecular weight of the sample can be larger than 100 kDa. The results of differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) showed that the isomeric segments of the three-arm PPO-PDLA- The structure of the composite crystal was established and its melting point was about 200 ℃, and there was no crystallization of PLLA homopolymer.Experimental results show that this is a new type of heat-resistant Acid (PLA) materials.