The Spreading and Adhesion of Polymers on Wool

Abstract

The application of polymers to wool is considered from the point of view of the surface free energies of wool and the polymers. A theory is developed explaining the effectiveness of different polymers in reducing felting shrinkage as heing due to the ease with which spreading can occur over the surface of the wool fibers. It is shown that a useful criterion for spreading is that γ, (the critical surface tension) of wool must be greater than γ_e of the applied polymer.

Spreading coefficients are calculated for various polymers on normal wool and on wool pretreated with chemical reagents. The spreading coefficients agree with the relatiye effects of chemical pretreatments, which can improve the efficiency of polymer treatments. The best pretreatments are those which increase the critical surface tension of wool from 45 dyne cm (normal wool) to 65-70 dyne cm.