Physical Properties of Fibers and Yarns of Partially Acety lated Cottons

Abstract

Samples of cotton of Deltapine, Rowden, and Stoneville varieties were partially acetylated as bulk cotton and as untreated 14/3 yarns to acetyl contents ranging from 9 to 26%. Breaking loads and elongations at break of single fibers, fiber bundles, and yarns were decreased by the partial acetylation up to about 17%, but showed a tendency to increase above 20% acetyl content. Moisture conditions have less effect on tenacity of yarns of 25% than on those with lower acetyl content. Tenacities of the acetylated yarns when wet were slightly lower, and when desiccator-dried were higher than those of the untreated controls. Below 15%, the relation of density to acetyl content was consistent with calculations based on the preferential reaction of amorphous cellulose in the initial stages of the reaction. Resistançe to heat degradation increased with acetyl content up to 25% acetyl. The pH of the water used to rinse the reacted yarns was an important factor influencing heat degradation. Maximum retention of strength occurred when the wash water was in the pH range of 10-11. A slight but consistent difference in heat resistance of the partially acetylated cottons was associated with differ ent varieties.