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 3 physical properties of water and water-derived fibre properties

In the absence of published information regarding the temperature dependency of water-derived poly(ethylene terephthalate) fibre properties, the findings reported for the thermally regulated interactions between water and 100% amorphous poly(ethylene terephthalate) materials were interpreted from the perspective of the amorphous domains that reside within semi-crystalline polyester textile fibres. This analysis suggests that the pronounced temperature dependent uptake of a commercial grade disperse dye on poly(ethylene terephthalate) fabric achieved during an aqueous dyeing process at temperatures between 30 and 130°C is the likely result of the combination of three separate, but inherently inter-related, thermally activated phenomena, namely, polymer structural relaxation, in which polymer glass transition assumes a dominant role, dissolution of disperse dye in the aqueous dyebath, as well as various water–fibre interactions, in the guise of water sorption, water molecule diffusivity, water-induced swelling and water-induced plasticisation. Although thermally regulated macromolecular relaxation processes adopt the principal role in dye uptake, temperature dependent dye solubility and water-derived fibre properties nevertheless likely provide crucially important supportive roles.