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 acrylic 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 successfully produce N-carboxyethylchitosan (CECS). Then, the cotton was treated with different concentrations 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 highquality dyeing properties, However, direct dyes showed higher exhaustion and fixation values, fastness 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 antibacterial activity towards Gram-positive bacteria was reported to be more than Gram-negative bacteria.

Keywords: Carboxyethylchitosan; antibacterial activity; cotton fabrics; direct dyes; dyeing; fastness properties.