Preferential uniplanar orientation mechanism of the (101) crystal plane of regenerated cellulose

Abstract

The molecular orientation behavior of regenerated cellulose, in both crystalline and noncrystalline phases, was investigated quantitatively under various conditions during coagulation‐regeneration from viscose solution and during drying of the resulting gel film. It was concluded that the stronger the tensions which arise parallel to the film surface during coagulation‐regeneration and drying of the gel film, the more prominent become the uniplanar orientation of the (101) crystal plane and planar orientations of the crystal b axis and noncrystalline chain segments, all parallel to the film surface and associated with considerable distortion and disintegration of the regenerated crystal. This conclusion suggests an orientation mechanism of the cellulose II crystal, namely, rotation of the crystal around the U₍₁₀₁₎ axis associated with slippage of the (101) crystal plane, the most highly hydrated and most readily dislocated plane, in the direction of the tension, which is also parallel to the surface of the film. The behavior of this type of uniplanar orientation of the (101) crystal plane is characterized semiquantitatively by comparing observed distributions of the orientation of crystallographic axes with those calculated on the basis of a relatively simple model for crystal orientation.