Small angle x-ray study of cellulose in cotton using correlation functions

Abstract

This work shows that the small angle X-ray scattering (SAXS) intensity of dewaxed cotton of local origin at 25°C deviates from Porod’s law establishing that cotton at 25°C falls under non-ideal two-phase structure characterised by continuous variation of electron density at the phase boundary. Therefore the mean square of the electron density gradient ‹|grad η|2› in isotropic structure is proportional to the fourth moment ∫s4I(s)ds, of the SAXS intensity distribution in the reciprocal space and to the second derivative of the correlation function in the origin. The above relation given by Vonk has been used to find the thickness E of the transition region along with the following important physical parameters. They are D, the average periodicity transverse to the layer, S/V, the specific inner surface, φ1 and φ2, the volume fraction of two phases, i.e., matter and void, lc, the length of coherence, l1 and l2, the transversal lengths, lr, the range of inhomogeneity and 2E/D, the volume fraction of the transition layer. Two values of E have been obtained by the method of Vonk and Ruland. The SAXS intensity data of cotton sample was obtained by a technique using a compact Kratky camera. © 1988 The Society of Polymer Science, Japan.