Birefringence, density, and tensile characteristics of oxycelluloses

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Abstract

Investigations have been carried out on the changes in the characteristics such as refractive index, density, single fiber breaking strength, and moisture regain of cotton fibers brought about as a result of oxidation with sodium metaperiodate and potassium dichromate-oxalic acid. The study has also been extended to sodium chlorite-treated and sodium borohydride-reduced oxycelluloses obtained from these oxycellulose products. Results indicate that in case of sodium metaperiodate oxidation, birefringence and density first increase, reach a maximum and then decrease sharply as oxidation is continued, while breaking strength decreases in the initial stages, reaches a minimum, and then increases in the later stages. With dichromate-oxalic acid oxidation, birefringence increases sharply during the initial stages of oxidation and after reaching a maxima, decreases as oxidation progresses, while there is a rapid increase in the values of density during the initial stages followed by a slow rise as oxidation is continued. In case of dichromate-oxalic acid oxycelluloses, breaking strength decreases continuously with the progress of oxidation. Results are interpreted in terms of changes in gross morphology and fine structure of cotton as a result of oxidation and subsequent chlorite and borohydride treatments.

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