Shrinkproofing of wool using benign methanolic potassium hydroxide and sericin biopolymer

Abstract

In this research work, wool fabrics are pretreated with methanolic potassium hydroxide and subsequently treated with the biopolymer sericin to impart shrink-proofing. The effects of key process parameters, namely the concentration of potassium hydroxide and the concentration of sericin, on the area shrinkage of wool are examined. The results indicate that wool pretreated with 0.02 M methanolic potassium hydroxide followed by 15 g/L sericin shows the least area shrinkage of 6%, compared with untreated wool. The fabrics are characterised using scanning electron microscopy, tensile strength testing, bending length measurement and yellowness index evaluation. The findings demonstrate that controlled hydrolysis of wool fibres, followed by sericin coating, provides a satisfactory anti-felting effect. The colour of the wool changes to off-white without adversely affecting handle, tensile strength or elongation. The proposed shrink-proofing method proves effective, as it is chlorine-free and employs benign potassium hydroxide along with sericin reclaimed from silk waste, offering a safer alternative to conventional chemical-based polymers.