STRUCTURE AND MECHANICAL-PROPERTIES OF NYLON-6.12 PREPARED BY TEMPERATURE SLOPE CRYSTALLIZATION .1. CRYSTALLIZATION OF ORIENTED SPHERULITICTEXTURES

Oriented spherulitic textures of a rod-shaped nylon 6.12 sample were c rystallized by the temperature slope method. Crystallization condition s were compared by changing temperatures and growth rates. Three types of textures (negative spherulites, positive spherulites, and spheruli tic aggregates) were observed by this method. The negative textures ap peared when the growth rate was less than 0.1 mm/h. Crystalline orient ation and mechanical properties of the textures were investigated by x -ray diffraction and microhardness measurements, respectively. The hyd rogen-bonded (010) planes were perpendicular to the growth direction i n the negative spherulite, while they were parallel to the growth dire ction in the positive spherulite. In the spherulitic aggregates, the t , axis was parallel to the growth direction, while the (010) planes fo rmed roughly an angle of 45 degrees with the growth direction. Due to the orientation of the hydrogen-boned planes, the negative texture exh ibited an anisotropy, with hardness values of 106 MPa and 137 MPa when measured perpendicular or parallel to the growth direction, respectiv ely.