Physicochemical changes on wool surface after an enzymatic treatment

Abstract

A new ecological method has been proposed for the shrink-proof finishing of wool, based on an enzymatic pre-treatment and chitosan deposition, ensuring dimensional stability after multiple washing processes. It was demonstrated that an enzymatic treatment using highly selected proteolitic enzymes causes a distinct decrease in the shrinkage of wool fabric. The present work is aimed at analyzing the physicochemical changes in the wool surface following an enzymatic treatment. In order to characterise these changes measurements of the electrokinetic potential of wool samples and the enzymatic bath were performed. An increase in the electronegative PCD potential of wool samples and the enzymatic bath during the process was observed. Also, the enzymatic treatment causes a change in the isoelectric point (IEP) value of wool, as obtained by the electrokinetic measurements. The amount of the individual amino acids released during the enzymatic treatment of wool was monitored by the HPLC method. Moreover, an XPS analysis of enzymatic-modified wool fabric samples and contact angle measurements were performed. The data obtained by the XPS method allowed comparison of the changes in the elemental concentration on the wool surface after enzymatic treatment. The results of the contact angle measurements demonstrated an increase in the wettability of the modified wool surfaces. The results obtained proved that very good correlations exist between the value of electrokinetic potential, HPLC results, XPS measurements, contact angle values and changes in the isoelectric point (IEP). © Springer-Verlag Berlin Heidelberg 2006.