Alterations in Structural and Mechanical Properties of Wool Fibers Versus Sheep's Age

Abstract

This study deals with changes in birefringence, degree of crystallinity, density, content of ortho and paracortex, tensile strength, elongation-at-break, and percent of medullated fibers in samples of wool taken from a permanently marked place on the side of a sheep during various periods of its life. It has been found that these charac teristics change with the age of the animal, their magnitudes mostly increasing. Partic ularly interesting are the changes in birefringence, which increases from 0.0090 at lamb's birth to 0.0128 after 365 days, and changes in the degree of crystallinity which vary within the range of 26-32%, depending on the fiber growth. It has also been noticed that the ratio of ortho to paracortex diminishes with the sheep's age and the tensile strength of the fiber increases.