DISTRIBUTION OF DIETHYLENE GLYCOL COMPONENT IN THE FINE TEXTURE OF POLYESTER FIBERS

Distribution of diethylene glycol (DEG) component in the fine texture of polyester fibers has been investigated by measuring the concentrations of DEG in the decomposed and the residual portions obtained by heterogeneous aminolysis of the fibers using monomethylamine. The result shows that the region having higher DEG content decomposes more easily in both fibers of polyethylene terephthalate (PET) and copolyester having DEG as one glycol component. The tendency becomes remarkable as the temperature of the heat treatment of the fibers prior to the aminolysis is increased. From the analyses of the data obtained by gel permeation chromatography of the residual portion and of the crystallinity by X-ray and infrared spectroscopy, it is shown that aminolysis proceeds successively from the amorphous region where amine can easily pass into. Even in the heat treatment of PET fibers, crystallization occurs by squeezing the DEG rich portion out to the amorphous region, resulting in the increase of DEG concentration in the amorphous region. The change in the dyeing behavior of fibers by heat treatment can be reasonably explained by taking account of the quality change of the amorphous region due to the increase of DEG.