45—The Effect of Treatment in Aqueous Phenol Solutions on the Physical Properties of Secondary Cellulose Acetate Filaments

Abstract

Fabrics which contain secondary cellulose acetate yarn are delustred commercially by treatment in hot aqueous solutions, usually solutions of phenol and soap. These treatments produce inside the filaments minute cavities which scatter light and reduce the lustre of the fabric. An undesirable result of the process is a weakening of the filaments, which in some cases is considerable. This paper gives an account of an investigation into the effect of concentration of phenol and of temperature on the following.(a) The mechanical properties of the yarn. The loss of strength was found to be accompanied by large changes in the load-extension characteristics of the yarn and was very largely independent of the presence of the delustring cavities.(b) The molecular structure of the filaments. In most cases the loss of strength was accompanied by an increase in crystallinity and a decrease in orientation.(c) The behaviour of the surface of the filaments during extension. The treatments, in general, affected the characteristics and intensity of the surface cracking and, in some cases, the cracks were associated with pronounced “necking”.(d) The submicroscopic structure of the filaments.The observations suggest that the loss of strength results partly from the reduction of chain orientation and partly from the formation of crystallites. Changes in the structure of the surface do not appear to be important.