Changes in Surface Properties and Dyeability of Polyethylene Terephthalate Fibre Pretreated with Selected Chlorinated Solvents

Abstract

Scanning electron microscopy (SEM) and X- ray diffractometry (XRD) analyses has been used to investigate the structure of polyester fibre surface before and after treatment in some chlorinated solvents; perchloroethylene (PCE), trichloroethylene (TCE), 1,1- dichloroethylene (1,1-DCE) and tetrachloromethane (TCM) for different times in relaxed condition at room temperature. The results of the scanning electron micrographs did not show any observable internal damage in the fiber structure. On the surface however, several changes such as presence of micro voids, roughness and scissions of varying shapes, magnitudes and spacing density have been observed. The intensity of the diffracted peaks from the X- ray diffractographs of the treated fibre also showed a fall compared to the control one which may be accounted for in terms of the surface structural changes earlier on observed. The pretreatment of the polyester fibre with the chlorinated solvents was found to improve the dye uptake of all the treated fibres in the order of TCE > 1,1-DCE > PCE > TCM; this may be due to the large increase in the inter surface area swelling and greater segmental mobility of polymer molecules. TCE was found to be the best among the four solvents in terms of improvement in dye uptake. The improvement in the fastness properties (wash and light) of the pretreated fabrics was also observed. The chlorinated solvents used in this experiment caused structural differences on surface structures of the polyester fibres and these changes are very crucial to the behaviour of the polymer in fibre processing for other essential usage.