DEFORMATION BANDS GENERATED BY ANNEALING ON THE EDGE OF ROLLED NYLON FILAMENTS

Abstract

The breaking strength and the elongation of drawn and rolled nylon filament decreased significantly by annealing without constraint at temperatures above 200°C. But these decreases are not observed in the specimens annealed under constraint to prevent the shrinking. On the edges of the specimens weakened by annealing deformation bands were observed, and when these specimens were redrawn, cracks were formed in the deformation bands, resulting in the final rupture of the specimen. Owing to the difference of deformation between the edges and the central region, the internal stress which acts parallel to the filament axis will be generated. When this internal stress is released by the motion of molecular segments at high temperatures, the deformation bands are formed. Results of electron micrscopic observation of these deformation bands also agree with this consideration.