Measurements of orientation in cotton fibres using polarized light

Abstract

The Becke line method of measuring refractive index was used on account of the irregular form of the cotton fibre. The variation in the calculated spiral angle of the fibrils is closely related to the variation in convolution angle and the data suggest that the average spiral angle in the original unconvoluted fibres may be the same for all varieties. A relation between cell length and spiral angle which holds for wood tracheids and bamboo fibres, also applies to cotton fibres if the "cell length" is taken as the average distance between reversals in spiral direction. Strength and initial Young's modulus are shown to be correlated with the degree of orientation calculated from the observed double refraction.