Abstract:

For the high-performance copolyester PET/PEG polycondensation process, a two-phase steady-state model of continuous melt polymerization in a disk reactor was established. The effects of reaction temperature, pressure, residence time and mass transfer parameters on the vapor phase composition, the number average molecular weight, by-product concentration and carboxyl end group concentration were analyzed. The results showed that the volatile components were mainly produced in the first half of the reactor. After z > 0.4, the total amount of volatile had been very small. The proportion of ethylene glycol to the vapor phase was very high, about 90%, while the content of diethylene glycol was very low, only about 0.5%. The molecular weight of copolymer increased with the increase of reactor temperature, vacuum degree, residence time and mass transfer coefficient, when the mass transfer coefficient was greater than 0.1 s^-1, the molecular weight of the copolyester at the reactor outlet almost did not change. At this time, it was no longer controlled by mass transfer, and the molecular weight of the final product could reach about 26000.

Key words: PET/PEG copolymer, melt copolycondensation, two-phase model, steady-state analysis

摘要：

针对高性能共聚酯PET/PEG缩聚过程，建立了圆盘反应器中连续熔融聚合两相稳态模型，模拟分析了缩聚反应温度、压力、停留时间以及传质系数对气相组成、共聚酯数均分子量、端羧基浓度以及副产物二甘醇和水浓度的影响。结果表明：挥发组分主要在反应器的前半部分产生，在z > 0.4后气相挥发总量已经很小；乙二醇占气相组成的比例极高，约为90%，而二甘醇的含量极低，只为0.5%左右；随反应器温度、真空度、停留时间、传质系数的增加，共聚酯产物的分子量增大，当传质系数大于0.1 s^-1后，反应器出口的共聚酯分子量几乎不再变化，此时已不受传质控制，最终产物的分子量约26000。

关键词: PET/PEG共聚酯, 熔融共聚, 两相模型, 稳态分析