Fine Structure of Viscose Rayon

Abstract

Quantitative x‐ray diffraction methods have been used to study the orientation of the cellulose chains and lateral ordering around the long chain axes in various commercial and experimental rayons. Lateral order can vary independently of orientation in cellulose, as is the case with other linear polymers such as the polyamides. The degree of lateral order obtainable by aqueous annealing of regenerated cellulose appears to be restricted by the structure originally set up. As noted by Sisson, the well‐known relations between yarn tenacity and orientation and elongation to break and orientation are not unique. At a given orientation, a range of tenacities and elongations are possible, depending upon the influence of other variables. Study of a series of yarns prepared under constant mechanical conditions showed that elongation to break increased with lateral disordering of the cellulose chains at constant orientation. The data support Baker's proposal that local chain disordering in any linear polymer favors higher extensibility. Some yarns of essentially the same orientation and lateral order have shown different properties indicating that other as yet undefined structural variables also have an important effect on physical properties.