Natural Dye Extracted from Vitex negundo as a PotentialudAlternative to Synthetic Dyes for Dyeing of Silk

摘要

Since the last decade, the application of naturaluddyes on textile material has been gaining popularity alludover the world, possibly because of the increasing awareness of issues concerning the environment, ecology and pollution control. The present paper investigates extraction of natural dye from leaves of the plant Vitex negundo,which is an abundant, cheap, and readily available agricultural by-product. Water extracts from V. negundo was used to dye silk fabrics. Optimum extraction conditionsudincluded pH 9, duration 120 min, and temperature 90 C.udOptimum dyeing conditions included dyeing pH 5 andudduration of 60 min. Potash alum, tannic and tartaric acidudwere used as mordants, all of which are benign to humanudhealth and the environment. Color strength and colorudcoordinates in terms of L*, a*, b*, C, and h were examined.udA range of shades were obtained when fabrics were dyedudwith different mordants and mordanting techniques. Theudextracted dye was tested for some of the eco-parametersudusing atomic absorption spectrophotometry and GC/MS.udThe test results were compared with set standards touddetermine the eco-friendliness of natural dye. Their concentrations were found to be lower than the stipulatedudlimits. Dyed samples were tested for antimicrobial activityudagainst gram-positive and gram-negative bacteria. Theuddyed silk fabrics showed acceptable fastness properties andudwere also found to possess antibacterial activity. It can be concluded that the abundantly available agricultural byproduct V. negundo has great potential to be effectivelyudutilized as a natural dye for silk.