Abstract

A series of wool keratin/hydroxymethyl cellulose sodium (CMCNa)/glyoxal composite membranes were prepared via solution blending and cross linking modification technology. The optimization of composite films preparation was critically investigated via orthogonal experimental design. Experimental results indicated that the cross-linking agent had a greater effect on the mechanical properties of films. Under the optimal condition (keratin/CMCNa weight ratio: 5.5, 0.3% glyoxal, reaction time: 1h, reaction temperature: 37°C), the composite membrane showed good tensile strength and maximum elongation, which can be used as film-forming agent in leather finishing. Moreover, in contrast to casein, the application properties of the leather finished by modified keratin composite film were measured: tensile strength increased by 11.3%, elongation at break improved by 25.7% as well as water vapour permeability by 3.76 %, and wet rub resistance fastness improved from 3 to 4. However, air permeability decreased by 15.1%. SEM and FTIR analysis verified that it has good compatibility, strong hydrogen bonds and covalent bonds formed between cross-linking agent and raw material molecules. The product might be great potential for application in leather finishing as film-forming agent instead of casein.