PET缩聚过程脱挥方式比较——抽真空及通氮气

Comparison of the way of removing small molecules in PET polycondensation process ——pumping vacuum and purging with nitrogen gas

抽真空及通氮气是 Ｐ Ｅ Ｔ缩聚过程脱除小分子的两种方式， Ｐ Ｅ Ｔ 间歇缩聚实验研究表明：通氮气脱挥时聚合度一直上升，而抽真空脱挥时聚合度趋向某定值；脱挥速度与通氮位置有关；通氮气脱挥得到的聚合物比抽真空脱挥得到的色泽白。

pumping vacuum and purging with nitrogen gas are two ways of removing small molecules from PET melts in PET polycondensation.Experiments of batch PET polycondensation show:The degree of polymerization is up continuously when small molecules is removed by purging with N 2,the degree of polymerization is up to a maximum value when small molecules is removed by pumping vacuum.The rate of removing small molecules is correlated to the position of leading N 2.The color of PET products obtained by purging with N 2 is better than by pumping vacuum.