The roles of polymer relaxation phenomena, aqueous dye solubility and the physical properties of water in the mechanism of adsorption of a disperse dye on poly(ethylene terephthalate) fibres: Part 4 further aspects related to polymer relaxation phenomena

Abstract To further investigate the contribution of polymer relaxation times to the mechanism of disperse dye adsorption on poly(ethylene terephthalate) fibres, the temperature‐dependent uptake of Teratop Yellow HL‐G 150% on both cotton and polyamide 66 fabrics at temperatures between 30 and 130°C was compared with that on poly(ethylene terephthalate) fabric. Although uptake of the commercial grade dye on polyester fabric is governed by the thermally regulated, broad glass transition of the water‐saturated poly(ethylene terephthalate) substrate, as this was not observed for either cotton or nylon 66 fabrics, the respective cellulose or polyamide 66 polymer glass transition does not present a major thermal impediment to dye uptake over the wide range of dyeing temperatures used. This is because the onset and end‐set temperatures of the glass transition of the water‐plasticised poly(ethylene terephthalate) material reside within the range of dyeing temperatures employed, whereas those of the water‐plasticised cotton and polyamide materials occur below the lowest dyeing temperature examined (30°C). The thermal dependency of disperse dye solubility also likely makes a meaningful contribution to the temperature‐dependent dye uptake observed for each type of fibre.