Effects of 7--Ray Irradiation on Filament

Studies have been carried out on the effects of 7-ray irradiation on physical and mechanical properties of isotactic polypropylene filament. Samples were irradiated in the presence of air as well as in vacuo at room temperature. The densities of the samples were almost unchanged by irradiation in vacuo, but considerably increased in case of irradiation in air. The degree of shrinkage at the flow temperature of the irradiated filament as well as the flow temperature decreased with increase in dose, except for a sample irradiated at a dose of 9.3x107r in vacuo.The tensile strength and elongation at break decreased by irradiation in vacuo, especially in air. Young's modulus and elastic recovery at room temperature did not change with dose. The changes in these properties by irradiation are presumed to be dependent on the presence of oxygen. 1