一次性塑料制品在人们日常生活中用量较大，但其废弃物具有体积大、性能稳定等特点，采用传统的掩埋和焚烧的处理方式都会带来严重的环境危害。可降解塑料是一次性塑料制品行业新的发展方向，受到广泛关注，主要用于购物袋、包装、农业生产等生活生产领域。煤化工生产路线合成乙二醇的过程中会伴随大量的副产物乙醇酸甲酯的产生，通过优化分子设计和聚合工艺，开发适合注塑和吹膜的材料，既能充分发挥煤化工副产品原料的优势，同时也能够开拓乙醇酸的用途范围。另外，通过煤基路线可以合成并获得丁二酸二甲酯和1,4-丁二醇，探索合成聚丁二酸丁二酯（PBS）的条件，有利于促进原料的来源更加多样化，对于拓宽煤化工产业链具有重要意义。本文主要探索乙交酯、乙醇酸的共聚反应，采用共缩聚和开环共聚方法对乙交酯、乙醇酸进行了共聚反应。首先尝试了利用聚对苯二甲酸/己二酸丁二酯为基础树脂进行共聚实验，获得产物的热性能、力学性能并不是太突出。之后以PBS为基础树脂与乙醇酸（乙交酯、乙醇酸甲酯）进行共聚反应，合成乙醇酸结构含量接近30%的共聚物，热性能均较弱；减低乙醇酸结构用量为15%，合成产物性能良好且相近，几种单体可发挥类似的合成效果。后尝试以聚乙醇酸嵌段与丁二酸、1,4-丁二醇共聚，仍难以形成高分子量嵌段共聚物；而后针对共聚物流动特性差的特点，分别以丁二酸、1,4-丁二醇、乙醇酸与适量丙三醇或季戊四醇进行长支化反应，获得具有长支链的共聚物，流变性能大幅度提高，且材料具有良好的热性能、力学性能和降解性能，反应的缩聚时间也大幅度缩短。与此同时通过开环共聚与扩链改性结合的方法，利用乙交酯及ε-己内酯进行共聚反应获得力学性能良好的共聚产物，产物具有良好的水解特性；之后探索用扩链剂1,4-丁二醇缩水甘油醚对共聚产物进行扩链，通过适量的扩链剂可以增加聚合物样品的拉伸韧性。除乙交酯的共聚改性研究之外，同时还以丁二酸二甲酯（DMSU）和1,4-丁二醇进行了酯交换法合成聚丁二酸丁二酯的研究，首先通过设计计算，完成了酯交换法合成聚丁二酸丁二酯过程的动力学过程模拟，计算出了酯交换过程和缩聚过程的活化能，对产物的结构、热性能、力学性能以及反应中副产物成分和聚合物酸值进行了测定分析，揭示了酯交换法的相对优势。
Disposable plastic products in daily life are huge in amount, but the waste of large volume, stable performance, using the traditional burial and incineration treatment will bring serious environmental problems. As a new development direction of disposable plastic industry, degradable plastics have attracted wide attention, mainly used in shopping bags, packaging, agricultural production and other areas of daily production. A large number of byproduct, methyl glycolate will be produced during the synthesis of glycol in coal chemical production route. By optimizing the molecular design and polymerization process, developing materials suitable for injection molding and film blowing can not only give full play to the advantages of byproduct in coal chemistry, but also expand the scope of use of glycolic acid. In addition, dimethyl succinate and butanediol can be synthesized and obtained through coal-based route. Exploring the conditions for the synthesis of poly(butylene succinate) is conducive to promote the diversification of raw material sources and is of great significance for broadening the coal chemical industry chain.In this thesis, we mainly explored the copolymerization of glycolic acid and glycolide. The copolymerization of glycolic acid or glycolide was carried out by the method of copolymerization via polycondensation and ring opening. Firstly, the copolymerization experiment using poly(butylene terephthalate/adipate) as the base resin was tried, and the thermal and mechanical properties of the product were not good. After copolymerization with glycolic acid (glycolate or methyl glycolate) based on PBS resin, copolymers with the content of glycolic acid structure close to 30% were synthesized, but their thermal properties were weak. By reducing the amount of glycolic acid structure to 15%, the properties of the synthesized products are good, and several monomers could play a similar effect. Later, we tried to copolymerize polyglycolic acid blocks with succinic acid and butanediol, but it was difficult to form high molecular weight block copolymers.Then, in view of the poor flow characteristics of the copolymer, we synthesized long chain branched poly(glycolate-co-butylene succinate) from succinic acid, butanediol, glycolic acid and appropriate amount of glycerol or pentaerythritol. The rheological property was greatly improved, and the material had good thermal, mechanical and degradation properties. The polycondensation time of the reaction was also shortened. At the same time, the copolymerization of ethyl ester and ε-caprolactone was carried out by the method of ring opening copolymerization and chain extension. The copolymerization products with high mechanical properties were obtained, and the products had good hydrolysis characteristics. To explore the chain extension effect of 1, 4-butanediol glycidyl ether on copolymerization products, the tensile toughness of polymer samples could be increased by the right amount of chain extender.In addition to the study on the copolymerization modification of ethyl ester, we also carried out the study on the synthesis of poly(butylene succinate) by transesterification with dimethyl succinate (DMSU) and 1,4-butanediol. Firstly, the kinetic process of the transesterification and the polycondensation process poly(butylene succinate) was simulated, and the corresponding activation energies were calculated. The structure, thermal and mechanical properties of the product, the by-product composition and the acid value of the polymer were determined, which demonstrate the advantages of transesterification.
