Electron beam irradiation of EPDM/PVC blend

Abstract

Blends of ethylene-propylene-diene-terpolymer, EPDM/polyvinyl chloride, PVC render poor mechanical properties as they are thermodynamically immiscible. In this work, the effect of irradiation on the EPDM/PVC blend was studied in order to enhance the mechanical properties through irradiation-induced co crosslinking of PVC and EPDM. The 50/50 EPDM/PVC blend was prepared by mixing in a Brabender Plasticoder at 170°C. The blend was then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 200 kGy in air and room temperature. The gel fractions, hardness, tensile strength, Young's modulus, and elongation at break of the blends were measured. Enhancement in properties of the blend such as gel fraction, hardness, tensile strength and Young's modulus of the blend have confirmed the positive effect of the irradiation on the EPDM/PVC blend achieving an optimum tensile strength at 50 kGy irradiation dose. The addition of crosslinking agent, trimethylolpropane triacrylate (TMPTA) provides excellent acceleration in irradiation-induced crosslinking in the blend. However, the blend can achieve an optimum tensile strength with good retention in Eb in the absence of TMPTA. This observation is attributed to the co-vulcanised state which is achieved in EPDM/PVC blend at slower curing rate of the blends.