MOLECULAR ORIENTATION IN VARIOUS TYPES OF POLYAMIDE FIBERS STUDIED BY THE FLUORESCENCE METHOD

Abstract

Molecular orientation in various types of polyamide fibers is studied by the fluorescence method. In the first place, molecular orientation in nylon-6 fibers is studied in detail. Effects of spinning conditions on the molecular and crystalline orientations and on the mechanical properties are discussed; then the changes of molecular orientation by drawing and heat treatment under various conditions are described. Molecular orientation in other types of nylon fibers is also studied.Comparing these data with those of X-ray and density measurements, it is considered that not only the random rotary motion of the non-crystalline chains but also the crystallization process are responsible for the variation of molecular orientation. The presence of planar type of orientation perpendicular to the fiber axis is explained by the lateral stretching of non-crystalline chains caused by the growth of the neighboring crystallites.