Influence of solvent pretreatment on dyeing performance of polyester yarns

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:calibri;mso-bidi-theme-font:minor-latin;="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The effect of trichloroacetic acid-methylene chloride (TCAMC) solvent system on the dyeability of three geometrically varying poly(ethylene terephthalate) yarns has been studied. The pretreatment was carried out at different concentrations of TCAMC for 5 min at about 30°C and the dyeability characteristics were studied making use of two different energy level commercial dyes at 115°C and 130°C. An enhanced dye uptake has been observed in all the cases studied. Increase in dye uptake depends on various factors besides the TCAMC concentration. The <i>L, a, b </i>colour coordinates were used to assess the change in colour, chroma, lightness and hue of the treated-dyed yarns. It has been observed that the treatment has greater effects on fibre morphology. The treatment leads to a high degree of swelling which facilitates easy penetration of dye molecules into the compact structure of the polymer. The unusual relationship between the increase in crystallinity and increase in dye uptake is explained. The overall fastness properties of the treated dyed yarns have been found to be good.</span>