COLOR MODIFCATION OF COTTON FIBERS WHEN TREATED WITH POLICARBOXILIC ACIDS

Abstract

Cellulosic fi bers are well known because of some properties such as confort when used as fi bers in cloths. However, some disadvanteges can be observed such as lack of dimensional stability and crease resistance. In order to minimise those properties some fi nishing treatments as crosslinking are used. A crosslinking agent widely used is dimetildihydroxiethylenurea (DMDHEU) but releases formaldehide which is carcinogenic. Polycarboxilic acids are considered as the ones that can replace DMDHEU. The use of these acids involve treatments at high temperatura (170-200º C) which can imply a change in color of the treated fabrics. Recent studies show that apart from crosslinking agentes they can be used as fi nishing resins to add some substancies to textiles in order to obtain a Smart textil. An example can be the use of those acids to link microcapsules to fabrics avoiding them to drop off from the fabric because of gravity. In this study we have evaluated different acids knowing which one reduces the yellowing effect. Moreover we could determine which were the conditions that minimise yellowing. It could be observed that the presence of the catalyst increases the crosslinking effect and reduces the color change. Also we concluded that temperatures higher than 180º C are worthless as they do not allow to increase the number of carboxyl groups.