Free Salt Dyeing by Treatment of Cotton Fabric Using Carboxyethyl Chitosan and Synthesized Direct Dyes to Enhance Dyeing Properties and Antibacterial Activity

Abstract

Aim: The purpose of this paper is to synthesize and characterize two new direct dyes based on chromenes derivatives. Background: The synthesis of carboxyethyl chitosan (CECS) by the reaction of chitosan and acryl-ic acid via Michael's addition reaction was conducted. Cotton fabrics were treated with CECS to enhance the exhaustion of dye, fastness properties, and antimicrobial activity of dyed fabric. Methods: Chitosan (CS) and acrylic acid were combined in Michael’s addition process to success-fully produce N-carboxyethylchitosan (CECS). Then, the cotton was treated with different concen-trations of carboxyethyl chitosan (0.5–5 wt.%) and then dyed by synthesized mono azo and diazo direct dyes based on chromene derivatives. Results and Discussion: The results regarding dyeing and antibacterial activity indicated high-quality dyeing properties, However, direct dyes showed higher exhaustion and fixation values, fast-ness properties, and the colorimetric CIE L*a*b* C*h° data of the dyed cotton fabric. Conclusion: Cotton fabrics treated with carboxyethyl chitosan and dyed with direct dyes were found to have higher antibacterial activity upon a concentration of 2.5 wt.%. In addition, the anti-bacterial activity towards Gram-positive bacteria was reported to be more than Gram-negative bac-teria.