Modification of quaternary ammonium salts of chitosan and dyeing processes of natural dye curcumin on cotton fabrics

In view of the low color depth(K/S value) and poor colour fastness of natural dye curcumin on cotton fabrics,the cationic modification agent of quaternary ammonium salts of chitosan was prepared from chitosan and (2,3-epoxypropyl) trimethylammonium chloride and applied to modify cotton fabrics.The dyeing effects of cotton fabrics with natural dye curcumin were analyzed by color indexes.The optimum modification processes were obtained by single factor tests.The dyeing liquor ratio was 1:50,cotton fabrics were treated with 4%(omf) modification agent at 80℃for 40 min;The dyeing processes of curcumin on modified cotton fabrics were optimized as follows,1:50 of dyeing liquor ratio,5%(omf) natural dye curcumin,dyed at 60℃for 40 min.The K/S value of cotton fabrics increased obviously under optimal modification and dyeing processes.The color fastness of modified cotton fabrics were better than that of unmodified cotton fabrics.Color fastness to washing to rubbing of modified cotton fabrics were improved 0.5-1 grade than unmodified cotton fabrics and met to the standards of Oeko-Tex Standard 100.