Differential Response of Cottons to Slack Mercerization

Abstract

Fiber bundle strength at 1/8-in. test length of cottons of low and intermediate maturity is found to improve on slack swelling in 10% solution (w/w) of NaOH. At a concentration of 16% there is a marginal further improvement in the tenacity values of these cottons, and beyond 16% the tenacity levels off. Cottons of very high maturity differ from the above in that the tenacity values of these cottons are unaffected by the slack swelling treatment with 10% NaOH, and further, on treatment with 16% solution the tenacity values register a decline and then level off at higher concentrations. The causes of such a differential response of cottons of different maturities towards slack swelling in alkali of different concentrations are discussed on the basis of morphological and structural changes which the fibers have undergone, namely: change in linear density, removal of strain, and change in percent crystallinity and orientation of the amorphous phase of the cellulose material.