The plasticisation model of dye diffusion: Part 10

Abstract The Flory–Fox and Gordon–Taylor models were used to predict the extent to which sorbed water reduces the glass transition temperature of poly(ethylene terephthalate) yarn as a function of moisture regain. The extent of water‐induced plasticisation predicted by the Flory–Fox equation concurs with average values of plasticisation reported for polyester fibres/polymers. Re‐evaluation of temperature‐dependent equilibrium moisture sorption data using the Williams–Landel–Ferry equation showed that thermally activated water sorption and the structural relaxation times of water‐plasticised poly(ethylene terephthalate) macromolecule are interconnected, thermally activated phenomena. The glass transition of hydrated polyester filaments likely extends from 50°C up to at least 80°C. The temperature dependency of equilibrium water sorption in polyester substrates is primarily governed by water‐induced plasticisation.