Changes in fibre structure of regenerated cellulose fibres such as degree of crystallinity and lateral order and cross-sectional shape, by treatment with aqueous alkali of various concentrations have been investigated experimentally.
Rayons of two types were used and compared; fibre S, ordinary viscose rayon having irregular section and non-uniform distribution of lateral order, Fibre X, special viscose rayon having uniform round section and uniform single-peak lateral order distribution.
Both fibers showed increases in crystallinity, after swelling and deswelling, but the magnitude of the change in low ordered fibre (S) was much greater. The skin effect of this fibre disappeared and the distribution of lateral order shifted to highly ordered level and showed similar curve to that of Fibre X.
Changes in physical properties of fibres by swelling treatment were also observed, and discussed on the relation between fibre structures and mechanical properties. It was concluded that physical properties of Fibre X are closely associated with crystalinity and orientation, whereas those of Fibre S are much more markedly effected by the skin-core structure.
