Dyeing, fastness and antimicrobial properties of woolen yarns dyed with gallnut (Quercus infectoria Oliv.) extract

The present study was conducted to investigate the dyeing, fastness, and antimicrobial properties of woolen yarns using gallnut extract as a natural dye. Comparative results of color fastness (fastness to light, wash, and rub) and colorimetric properties (CIELab and color strength (K/S) values) of dyed woolen yarns were studied to quantify the effect of mordants. The antimicrobial activity of gallnut extract before and after application on woolen yarn was tested against common pathogens Escherichia coli, Staphylococcus aureus, and Candida albicans. Gallnut extract proved very effective in inhibiting microbial growth, both in the solution phase as well as after application on wool. A reduction in antimicrobial activity was observed when mordanted samples were examined. The wash durability of antimicrobial activity was also evaluated after one, five, and ten washing cycles. The antimicrobial finish was found to be semi-durable.

► The systematic study for investigating the possibility of dyeing and antimicrobial finishing of wool yarn with gallnut extract has been performed.
► It is the first report on effect of tin and alum mordants on antibacterial and antifungal activity of gallnut dyed woolen yarn.
► Results obtained indicate gallnut extract can fruitfully used for durable dual functional finish (producing color as well as antimicrobial effect) on woolen yarns.
►  Reasonable lab scale costs of finishing were also reported in the manuscript.