Surface Modification of Polyamide 6,6 Fabrics with an Alkaline Protease – Subtilisin

Subtilisin treatment is feasible in benign conditions, and yields a clean, dynamic approach for Polyamide 6,6 (PA 6,6) modification. In this study, the water contact angle (WCA) method, capillary height and moisture regain were used measure hydrophilicity. To characterization the modification, the scanning electron microscope (SEM), amino group quantification and x-ray photoelectron spectrometry (XPS) were used. Fabric burst strength and hand properties were characterized. Optimum conditions for subtilisin treatment were found to be 55oC, neutral pH with 10% (owf) enzyme concentration for a fixed 90 min treatment period. X-ray photoelectron spectrometry (XPS) results showed that carboxyl groups were produced on the modified fiber surface. The modified fibers showed much improved hydrophilicity as indicated by reduced wicking time, improved capillary height and moisture regain percentage. The creation of carboxylic acid group sand increased number of amino groups detected on the fabric surface may positively influence hydrophilicity. In comparison to harsh alkali modification, the enzyme treatment led to smaller weight loss. In general, enzymatic treatments- a more eco-friendly alternative to alkaline treatments, resulted in a significant improvement in surface properties of PA 6,6 fabrics.