Properties evaluation of sodium nitrite treated chitosan-cotton fabric

Abstract

In this study, chitosan coated-cotton fabric was prepared and then treated with sodium nitrite under mild condition, aiming at the partial removal of surface-chitosan in order to solve the problems of surface dyeing and fabric stiffness. The results showed that sodium nitrite treated chitosan-fabric exhibited an improvement of dyeability (higher dye exhaustion and color strength) when compared to untreated fabric. The improvement in dyeability was due to the availability of chitosan amino groups which had an affinity to anionic dyes including reactive dyes. Other fabric properties were evaluated. The results showed that color fastness properties (crocking fastness and light fastness) and fabric stiffness were found comparable to those of dyed untreated fabric (commercial dyeing). These findings led to the conclusion that problems of poorer fastness properties and stiffness arising from chitosan coating onto cotton fabric were minimized by sodium nitrite treatment under mild condition which resulted in the partial removal of chitosan coated film present on the fabric surface. The remaining chitosan on the fabric surface showed its ability of enhancing reactive dyeability without causing interference to fabric’s fastness properties.