Some Relationships between Dyeing Kinetics of Polyester Fibres and Their Structural Changes Caused by Heat‐Treatment and Dveine Conditions

The rate of dyeing of a poly (ethylene terephthalate) has been characterized as a function (a) of the tension applied before heat setting, (b) of the shrinkage allowed during heat setting, and (c) of the tension applied before dyeing. Very small variations in applied tension lead to very significant differences in rate of dyeing. Furthermore, in order to correlate the dyeing results with changes in the fibre, the structure of the polyfethylene terephthalate fibre was determined as a function of the tension applied before either heat setting or dyeing. The structural parameters studied were crystallinity, crystalline orientation, birefringence, amorphous orientation factor and water swelling at 130d̀C. The variations in dyeing kinetics may be due to changes of amorphous orientation on the one hand and to changes in tortuosity, size and volume of pores on the other.