Wool consists of the cortex, overlapping scales (sharper and more protruding than those of hair) that may expand at their free edges causing fibers to intermesh; elasticum, the inner layer; and a core. When soaked, the elasticum and core contract, shrinking the fiber. Elasticity resulting from the molecular structure of wool and resiliency from its crimp make wool fabrics crease resistant. Fine wool will stretch one third its length. Wool is warm because its fibers are nonconductors of heat and its crimp permits it to enmesh still air. It is highly absorbent and releases moisture slowly. Its tensile strength is one fourth greater than that of cotton. A protein compound of complex chemical composition, it is soluble in hot caustic soda.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.