51—A COMPARISON OF METHODS OF MEASUREMENT OF YOUNG'S MODULUS FOR KERATIN FIBRES

Young's modulus has been measured for several types of keratin fibre by a variety of means, including ‘static’ or load–extension methods, an oscillating beam, and an oscillating-fibre cantilever, As a result of these measurements, it is concluded that the Young's modulus for extension of the fibre as obtained from the low-frequency oscillating beam is a little higher than that obtained from ‘static’ measurements and that the difference may be accounted for by contributions from work-hardening effects and by practical differences at very definition of the modulus as well as by the small frequency-dependence at very low frequencies. Young's modulus for bending, on the other hand, cannot be reconciled with simple extension results. High-frequency longitudinal results are also different from the low-frequency values reported here, presumably because, in the high-frequency case, only the very strongest chemical bonds are involved, whereas, for relatively low-frequency measurements, weaker bonds associated with...