Hygral Expansion Behavior of Woven Wool Fabrics

Abstract

The interyarn forces present in an unset pure wool gabardine fabric and two other fabrics obtained by subjecting the unset fabric to different levels of permanent set by dyeing under different conditions have been assessed by determining the extent to which the length of the warp yarn changes on release from the fabrics at different regains. As the level of permanent set increases, the interyarn forces at saturation are reduced through stabilization of the bending strains. On drying, cohesive setting sta bilizes the residual bending strains, and this effect appears to be the dominant one in reducing interyarn forces. The effects of fiber deswelling in reducing interyarn forces (and of fiber swelling in increasing the forces) are relatively unimportant. At low regains, longitudinal strains in the weft yams are evident in each fabric. The changes in fabric geometry that occur are rationalized in terms of the combined effects of fiber swelling/deswelling and the interyarn forces.