Interactions of Nonaqueous Solvents with Textile Fibers

Abstract

Pretreatment of polyester yarns with a strongly interacting solvent (dimethylformamide) leads to modifications of the fiber structure which permit rapid diffusion of even “high-energy” disperse dyes under atmospheric conditions without the addition of carriers. A comparison of the effects of solvent pretreatments with the effects of thermal pretreatments on the dyeing behavior has been carried out. Pretreatment in a strongly interacting solvent leads to a high degree of swelling and at higher temperature to the formation of crystallites within the swollen structure. It appears that the swollen structure can be stabilized, depending on the size and stability of the crystallites formed, leading to cavitation and void formation upon subsequent removal of the interacting medium. It is suggested that a rigid pore mechanism of dye diffusion becomes operative in this structure, as opposed to the free volume mechanism of diffusion in thermally-treated polyester yarns.