Abstract
The relationship between tensile recovery and elongation is measured in various loading times, loads during recovery and recovering times with fibers of polyvinyl alcohol and its derivatives, silk, viscose rayon, acetate rayon and perlon L. From the tensile recovery-elongation curves these fibers are classified into three groups, e. g. cross-linkage type, side-chain type and steric hindrance type. Heat-untreated, heat-treated, and tere-phthalized polyvinyl alcohol fibers and perlon L are classified into the first type, formalized, butyralized, and nonalized fibers into the second type, and benzalized fiber, acetate rayon, silk, viscose rayon into the last type. In the cross-linkage type tensile recovery in higher elongation is better than that in lower elongation with the exception in very short loading time. In the steric hindrance type the minimum value in recovery-elongation curve rarely appears, and the effect of load during recovery and loading time for recovery are relatively small. The side-chain type shows the intermediate behavior between the other two types, but the effect of load during recovery is the greatest.
