X‐ray diffraction and infrared spectra studies on the fine structure of rayon improved by high temperature steaming

Abstract

Five samples of rayon containing two high tenacity rayons and three textile rayons of viscose and Bemberg types were heat‐treated with high temperature water or steam (110–210°C.) for a few minutes or seconds, and the change in the fine structure was investigated by means of x‐ray diffraction and small‐angle scattering. An additional study by infared spectra was carried out on cellulose films similarly heat‐treated. The crystallinity increased with increasing temperature and extension of the treating time within the range of less than 10%. Crystallites thicken laterally and grow into those of a higher order. Newly formed crystallites are of cellulose IV. The change is more striking in the high tenacity rayon than in the textile rayons. The remarkable reduction in the degree of swelling is considered to be due partially to such development of crystallinity. No clear conclusion could be drawn as to the contribution of junction points in the amorphous region.