Antimicrobial activity of silk treated with Aloe-Vera

Natural Silk in its native form is made up of the filament fibroin, coated with sericin - gummy matter which is antimicrobial in nature. However, sericin is removed during the pretreatment process. Silk being a natural and hygroscopic, fiber gets attacked by microbes easily. Hence antimicrobial treatment can add value to the wear and care of silk textiles. Synthetic antimicrobial agents may be toxic and even carcinogenic and hence the natural and eco-friendly antimicrobial agents are good substitutes for imparting the desired properties. In the present paper, ready for dyeing (RDF) silk fabric was treated with Aloe-Vera using 1,2,3,4-butanetetracarboxylic acid (BTCA) as crosslinking agent and sodium hypophosphite (SHP) as catalyst. The treated fabric with a concentration of 15 % of Aloe-Vera showed excellent antimicrobial properties. Since BTCA was used as a crosslinking agent, crease recovery angle, improved with minimal loss in breaking and tearing strength. The mechanism of treatment of Aloe-Vera is found to be chemical binding with silk and not simply of coating or impregnation. FTIR studies showed that the carboxyl side groups and short chain amino acids side groups act as sites for BTCA crosslinking interalia chemical binding of Aloe-Vera. SEM studies revealed that no coating or tangible impregnation on the surface of the fiber is visible substantiating the chemical binding phenomenon. This is further substantiated by the durability of the finish to dry cleaning of treated silk. Since Aloe-Vera is a natural product and BTCA is an eco-friendly resin, the treatment of silk with Aloe-Vera is eco-friendly in nature.