Application of a fibre‐reactive chitosan derivative to cotton fabric as a zero‐salt dyeing auxiliary

Cotton fabric has been treated with a fibre‐reactive chitosan derivative containing quaternary ammonium groups, O‐acrylamidomethyl‐N‐[(2‐hydroxy‐3‐trimethylammonium)propyl]chitosan chloride (NMA‐HTCC). Cotton treated with NMA‐HTCC has been dyed with direct and reactive dyes without the addition of salt. The colour yield was higher than that on untreated cotton, despite the addition of a large amount salt in the latter case. After dyeing, cotton treated with NMA‐HTCC gave better wash fastness than the untreated cotton. The light fastness was however inferior to that on untreated cotton. The antimicrobial activity of cotton treated with NMA‐HTCC against Staphylococcus aureus was considerably lower after dyeing, probably due to the antimicrobial effect of the cationic group on NMA‐HTCC being blocked by its combination with the anionic dye.