Moisture sorption/desorption of protein fibres

Structurally wool and hair fibres are a group of cuticle and cortical cells held together by the CMC. The diffusion properties of these keratinized fibres are known to be governed by the CMC which is formed mainly by internal lipids. Water exerts a large influence on the properties of keratin tissues. The differences in water adsorption and desorption behaviour of wool and hair with and without internal lipids were studied. The isotherms for these keratinized fibres behaved as expected with a characteristic hysteresis between uptake and desorption. A higher moisture regain was obtained for the extracted fibres, which was more marked for human hair. Wool fibre diffusion coefficients were smaller than those obtained for hair. Lipid extraction of both keratinized fibres increased the diffusion coefficients. Thus, the lipids in these two fibres play a key role in maintaining adequate water permeability.