Abstract

Ashis Narayan Amita Banerjee, Dibyendu Bikash Datta*, Rajiv Munshi and Debasish Das

Polycarboxylic acid compounds such as butane tetra carboxylic acid (BTCA), cyclopentane tetracarboxylic acid, (CPTA), and citric acid offer an environmentally friendly, non-toxic, and safe alternative to the use of toxic formaldehyde condensate resin as a crosslinking agent for silk. However, the sodium salts of phosphoruscontaining mineral acids used as esterification catalysts with such polycarboxylic acids are not environmentally friendly in view of their reported adverse effects on the aquatic environment and soil. Also, finishes based on such non-polymeric polycarboxylic acids cannot retain or improve the strength and moisture-regain characteristics of silk. Moreover, most polycarboxylic acids are too expensive for practical exploitation. In view of the above, the present work was aimed at establishing the optimum condition for the application of maleic acid on silk fabric in the presence of ammonium persulphate as the free radical polymerization catalyst and trisodium citrate as the esterification catalyst. Water-soluble chitosan with varied concentrations of 0.5-2 g/L was also incorporated in the finishing bath to impart antibacterial activity to the fabric along with the easy-care characteristics. Evaluation of attainable changes or improvements in the silk fabric properties in respect of tensile strength, wrinkle recovery, flexibility, antimicrobial and moisture regain on such treatments have been done. Also, changes in the chemical nature of silk fabric on such modifications have been studied by infrared spectroscopy and reported in the article. The study recommends the thermal curing system is conducive to the production of chitosan and maleic acid-treated eri silk fabrics with antibacterial and easy-care properties, without a significant loss in strength properties.