高黏度聚酯的醇解工艺及其溶胀预处理研究  

Alcoholysis process and swelling pretreatment of high-viscosity poly(ethylene terephthalate)

作　　者：张驰 乌婧 ZHANG Chi;WU Jing(State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,College of Materials Science and Engineering,Donghua Univeristy,Shanghai 201620)

机构地区：[1]东华大学材料科学与工程学院纤维材料改性国家重点实验室,上海201620

出　　处：《合成纤维工业》2024年第1期16-22,共7页China Synthetic Fiber Industry

摘　　要：以乙二醇(EG)为解聚剂分别醇解特性黏数为0.670,1.014 dL/g的聚对苯二甲酸乙二醇酯(PET)切片及两者的混合物,对醇解产物进行了表征;通过单因素控制法考察了反应温度、EG与PET摩尔比、反应时间、催化剂添加量对醇解产物产率的影响;针对高黏度PET切片难以醇解的问题,提出了一种溶胀预处理工艺,研究了溶胀预处理PET切片的醇解动力学。结果表明:不同黏度PET切片的醇解产物的化学结构基本一致,主产物均为对苯二甲酸双羟乙酯(BHET);高黏度PET切片醇解体系的反应温度高于低黏度PET切片,高黏度PET切片适宜的醇解工艺为EG与PET摩尔比141、催化剂添加质量分数0.5%、反应时间240 min、反应温度200℃,此条件下产物BHET的产率为48.65%;高黏度PET切片在130℃经溶胀预处理后,结晶度由30.95%降至25.25%,反应速率常数由0.1319 min-1提高至0.1719 min-1,醇解速率大幅提高,溶胀预处理适宜的温度为高于PET切片的玻璃化转变温度且比其结晶温度低20~30℃。Ethylene glycol(EG)was used as a depolymerizing agent to alcoholyze polyethylene terephthalate(PET)chips with intrinsic viscosities of 0.670 and 1.014 dL/g,respectively,and their mixtures.The alcoholysis products were characterized.The effects of reaction temperature,EG to PET ratio,reaction time and catalyst addition on the yield of alcoholysis products were investigated by a single factor control method.A swelling pretreatment process was proposed to solve the difficulty in the alcoholysis of high-viscosity PET chips,and the alcoholysis kinetics of PET chip exposed to swelling pretreatment were studied.The results showed that the chemical structure of the alcoholysis products of PET chips with different viscosities was basically the same,and the main product was dihydroxyethyl terephthalate(BHET);the high-viscosity PET chips required the reaction temperature of alcoholysis system higher than that of the low-viscosity PET chips;the yield of BHET product was 48.65%under the suitable alcoholysis process conditions for high-viscosity PET chips as follows:the molar ratio of EG to PET 141,0.5%catalyst by mass fraction,reaction time at 240 min and reaction temperature 200℃;the crystallinity of high-viscosity PET chips decreased from 30.95%to 25.25%,and the reaction rate constant increased from 0.1319 min-1 to 0.1719 min-1,the alcoholysis rate was significantly increased after swelling pretreatment at 130℃,and the rational swelling pretreatment temperature was higher than the glass transition temperature of PET chips and 20-30℃lower than the crystallization temperature.

关 键 词：聚对苯二甲酸乙二醇酯 乙二醇 醇解 溶胀预处理 醇解动力学 

分 类 号：TQ340.68[化学工程—化纤工业]