Shrinkage properties of peroxide-enzyme-biopolymer treated wool

Incorporating an enzyme in the alkaline peroxide treatment bath enhances wool wettability and the effectiveness of subsequently applied chitosan biopolymer. Wool whiteness is also significantly enhanced. Wool knitted fabric thus treated is shrink resistant at the machine-washable level, which is one of the most important end-user demands. The formation of ionic bonds between the new sulphonic groups generated on the wool fiber surface and chitosan contribute to the shrink resistance of H2O2 + enzyme/chitosan treated wool. As a result of excessive increases in enzyme concentration in the peroxide bath, the wool surface cysteic acid content decreases, thus diminishing both the efficiency of post-applied chitosan solution and the shrink resistance.