DEFORMATION RESISTANCE IN ORIENTED NYLON-6

Initially spherulitic nylon 6 was textured into a quasi-single crystal form by plane-strain compression at 170-degrees-C in a deep channel-die to a compression ratio of 4.0, followed by cooling under pressure to room temperature. The resulting material, having orthotropic symmetry with quasi-single crystalline perfection, had a dual morphology in which the normals of the crystallographic (100) planes equipartition at +/-21-degrees with respect to the constraint direction of the plane-strain deformation. This highly textured material, having relatively large dimensions in all directions, was used to study the elastic and plastic anisotropy of the actual constituent lamellar crystallites. As a result, a complete set of nine elastic compliances of the orthotropic sample were measured by a simple direct technique and were related to the monoclinic crystal properties. In addition, detailed measurements were made of the plastic anisotropy of this textured material to establish that plastic response of the actual monoclinic nylon 6 crystallites is derived principally from three crystallographic slip processes consisting of the (001) [010] and (100) [010] chain slip systems and the (001)-[100] transverse slip system. The plastic shear resistances of all these slip systems were found to increase substantially with increasing compressive stress acting across the slip planes. Among these three deformation mechanisms, (001)[010] chain slip is the easiest system to be activated.