Maturity and Dynamic Elastic Modulus of Cotton Fibers

Abstract

The polarized-light method was used to select mature and immature individual fibers from each of four maturity standard cotton samples. The dynamic elastic modulus, or the sonic modulus, of the selected fibers was determined by the pulse-propagation method at different static strain levels, and continuous dynamic modulus-strain curves and dynamic stress-strain curves were obtained for each fiber type. In general, the maturity of individual cotton fibers influences the general shape of the dynamic modulus-strain curves in two ways: the curve is shifted to the left along the strain axis, and the initial slope becomes steeper as the fiber maturity becomes greater. Recognition of the variation in helix angle through the fiber cross section provided a satisfactory explanation for the experimentally obtained facts. Individual fibers of relatively high maturity were characterized by a high initial slope of the dynamic modulus-strain curve.