Degree of lateral order in various rayons as deduced from x‐ray measurements

Abstract

AbstractX‐ray measurements on 16 different specimens of regenerated cellulose reveals that there exists a pronounced negative correlation between the integrated intensity of the 101 interference and its halfwidth. The 101 plane is a preferred cleavage plane and represents the lamellar plane of the ribbon‐shaped crystallites. Variations in the intensity of the other interferences are much less or nonexistent. These results show that the degree and the perfection of lateral order according to the 101 and 002 planes is little at variance, but that order according to the 101 plane is extremely variable in such a way that if the average thickness and (or) perfection of the lamellae increases, the total number of well‐ordered 101 plane contacts diminishes. As a possible explanation of this phenomenon it is suggested that various degrees of recrystallization with reference to this particular plane (i.e., various degrees of lateral order) may be associated with the various rayon specimens. This, however, does not necessarily imply differences in the total amount of ordered substance. This explanation is corroborated by the fact that cellulose acetate fibers which were previously allowed to “recrystallize” by heating in methanol, after saponification yield a rayon with a particularly sharp, but also particularly weak, 101 interference, without exhibiting a higher total percentage of ordered substance than the saponification products of acetate treated in this manner.