The effects of electron beam irradiation on the morphology, mechanical properties and heat and hot oil resistance of a thermoplastic elastomeric blend of 50/50 nylon 6 and HNBR rubber were investigated. The morphology of the blend was studied by scanning electron microscopy, with special reference to the effects of processing via injection moulding and the radiation dose. Irradiation of extruded pellets at low doses and subsequent injection moulding improved the blend morphology, thereby enhancing the mechanical properties. The tensile strength of the blend increased with radiation dose. The irradiated blends had excellent hot oil resistance and the tensile strength of the blends did not change much after ageing at 150 • C for 72 h. Incorporation of 10 phr SRF black to the blend greatly improved the tension set property.

The effects of electron-beam irradiation on morphology, mechanical properties and on the heat and hot oil resistance of the thermoplastic elastomeric blend of 30:70 and 70:30, nylon 6 and hydrogenated nitrile rubber (HNBR) were investigated over the dose range 0-8 Mrad. The insoluble content of blends increased with increase in the radiation dose. The morphology of the blend was studied in scanning electron microscopy, with special reference to the effect of radiation prior to processing via injection molding. Irradiated pellets showed better mechanical properties after injection molding compared with irradiated sheets at low radiation dose. The observed differences in mechanical properties are explained on the basis of morphology of the blend. The blend properties were also found to have a strong dependence on nylon content. It was found that the blends rich in nylon had superior mechanical properties, hot oil and solvent resistance, whereas blends with higher HNBR content had better set and heat resistance. The effect of radiation on interaction in these blends was also evaluated and was found to induce possible inter-chain crosslinking in the blends.