FIBRILLAR STRUCTURE AND DEFORMATION-BEHAVIOR OF REGENERATED CELLULOSE FIBERS .2. ELEMENTARY FIBRILS AND DEFORMATION

Six types of regenerated cellulose fibres, each of them based on several samples of different origin, have been investigated by means of transmission electron microscopy, wide-angle X-ray diffraction, small-angle X-ray scattering, birefringence, mechanical testing and swelling. It could be shown that above an elongation of 1%, stress-strain behaviour results from an orientation of the elementary fibrils and a disintegration of their clusters. Dissociating clusters cause a yield region, stable clusters and early stress break of the fibres. Clusters reduce the fibrillability of the fibres and their swelling in water and sodium hydroxide. The extent of the clusterification depends upon the conditions of fibre generation. The stress-strain behaviour of mercerized fibres results from an orientation of the disordered molecular segment in the defect zones between the crystallites.