Stress-Relaxation and Permanent Set in Keratin Fibers

Abstract

Variation of force with time in water for single wool and hair fibers stretched at both 10% and 40% extension was measured at various temperatures between 20° C. and 100° C. It was shown that at 100° C. and 40% extension the force after 1 hr. (the remanent force) was mainly elastomeric, and that between 60° and 70° C. a second order transition occurs for the stretched wool fiber in water. Chemical treatments which accelerate or retard the ability of a fiber to permanently set also reduce or in crease the value of the remanent force in the fiber.