Microwave versus Conductive Heating – Their Effect on the Solvent-assisted Dyeing of Polyester Fibre with Anthraquinonoid Disperse Dyes

The rates of dyeing of polyester fibre with amino- and hydroxy-substituted anthraquinones in aqueous N,N-dimethylformamide (DMF) using microwave and conductive heating have been compared. Structural changes, commonly associated with interactions between DMF and polyester fibre, were limited and minimal shrinkage occurred due to the low DMF to water ratio and short dyeing times. Tensile properties reflected this minimal shrinkage through increased elongation at break, and differential scanning calorimetry also indicated that structural changes were minimal. Microwave radiation increased dye diffusion, shrinkage, and elongation at break compared to conductive heating