聚对苯二甲酸乙二醇酯合成基本原理Ⅱ.聚对苯二甲酸乙二醇酯的合成

Basic principles of polyethylene terephthalate synthesisⅡ. Synthesis of polyethylene terephthalate

概述了聚对苯二甲酸乙二醇酯(PET)合成的基本原理,以及由对苯二甲酸乙二醇酯(BHET)单体经缩聚反应合成PET的反应机理、合成过程中的主要化学反应,详述了BHET缩聚合成PET的主要影响因素。由BHET缩聚合成PET属于逐步缩合聚合过程,缩聚过程中存在多个化学反应,包括链增长反应、链降解反应及网状结构凝胶物生成的副反应。BHET缩聚合成PET的影响因素主要有催化剂种类及其用量、稳定剂种类及其用量、反应温度、反应釜余压及物料的液层厚度等。今后,在PET及其共聚酯的合成中,应加大无毒催化剂的使用与推广、非石油基原料的开发及化学改性共聚酯的开发,以及废旧聚酯的化学法回收再生利用。

The basic principle of polyethylene terephthalate(PET)synthesis,the reaction mechanism of PET synthesis from ethylene terephthalate(BHET)monomer by polycondensation and the main chemical reactions in the synthesis process were summarized.The main influencial factors on the synthesis of PET from BHET by polycondensation were described in detail.The synthesis of PET from BHET polycondensation is a step-by-step condensation polymerization process,which comprises many chemical reactions,including chain growth reaction,chain degradation reaction and side reaction of mesh structure gel formation.The factors affecting the synthesis of PET from BHET by polycondensation mainly include the type and amount of catalyst and stabilizer,reaction temperature,reactor residual pressure and liquid layer thickness.The use and promotion of non-toxic catalysts,the development of non-petroleum-based raw materials and chemically modified copolyesters and the chemical recycling of waste polyester should be enhanced in the synthesis of PET and its copolyesters in the future.