Radiation-induced cross-linking of polyethylene

The effect is assessed of the admixtures of unsaturated polyester resins and acrylate resins on the physical and mechanical properties of radiation cross-linked polyethylene. The results were compared with the properties of polyethylene to which triallyl cyanurate was added as a cross-linking agent. Homogeneous mixtures were prepared by calendering at elevated temperature; for irradiation accelerated electrons in doses of 6g, 120 and 180 kGy were used. Evaluated for the individual samples were the structural tensile strength and ductility, the static modulus of elasticity in shear, the loss factor, the maximum of mechanical losses defined by the loss factor, and characteristic temperature T corresponding to glass transition temperature Tsub(g). The compositions using triallyl cyanurate show higher increase in the whole system rigidity than those with unsaturated polyester resins and acrylate resins. Thus, higher cross-linking can be achieved using triallyl cyanurate and irradiation. In most evaluations, a significant improvement of properties could be seen when doses up to 120 kGy had been used. For higher doses (180 kGy) a decrease was recorded while in compositions comprising 10% of triallyl cyanurate improved mechanical properties were shown even at these radiation doses. (B.S.)