16—THE CRIMP OF WOOL FIBRES AT VARIOUS REGAINS

The crimp parameters of merino-wool fibres, i.e., the uncrimping energy and stress, decrease with an increase in relative humidity from 5.14 × 103 g cm/cm3 and 0.149 × 106 g/cm2 at 0% r.h. to 0.37 × 103 g cm/cm3 and 0.021 × 106 g/cm2 at 100% r.h., i.e., decreases of 93 and 86%, respectively. The decrease in the uncrimping parameters is linearly related to the increase in the ‘bound’ or ‘localized’ water up to the solution region of the wool-water isotherm. In the solution region, the crimp parameters appear to be associated with the ‘loose’ water. It is suggested that the contribution of the matrix phase of the fibre (crimp A) to the over-all crimp decreases with an increase in relative humidity until in water the main crimp is related to the microfibrillar phase (crimp B). The value of the drying uncrimping stress measured in this study, i.e., 1.25 × 108 dyn/cm2 is close to the value of 1.63 × 108 dyn/cm2 obtained previously for the ‘hygrostress’ at zero elongation, which indicates a parallelism between the two phenomena.