The Recovery of Crimp of Wool Fibers

In this work the uncrimping force and energy are used to characterize the crimp of wool fibers. These parameters are measured through the load-extension curves of single wool fibers. It seemed necessary to investigate the stability of the uncrimping energy and force. This stability is referred to as crimp recovery. The dependence of crimp recovery on recovery times as well as on the amount of extension was studied. It was found that for immediate recovery the crimp decreases, and that this decrease varies with the percent of final extension of the fibers. When the fibers are kept in a relaxed state after the final extension for various times, it is found that the crimp recovery is almost complete after 24 hr of relaxation; with smaller times of relaxation the crimp recovery increases with time, while the extent of the recovery depends on the amount of final percent of extension—the higher the extension the lower the recovery. 1 Instron Engineering Corporation, Canton, Mass. 2 American Society for Testing and Materials.