Abstract
In this work low density polyethylene (LDPE) and ethylene vinyl acetate (EVA) were blended in the presence of trimethylol propane trimethylacrylate (TMPTMA) (0 to 6 phr). The resultant blends were irradiated with a 3 MeV electron-beam resulting in dosages of 0 to 240 kGy using a rhodotron accelerator system. The effect of radiation exposure on the LDPE/EVA/TMPTMA blend properties were investigated with respect to gel content, tensile strength and elongation up to breakage of the blends. The findings indicate that increasing EVA and TMPTMA content yield tighter network structures through enhanced blend crosslinking, which is a direct consequence of irradiation. For pure EVA significant tensile strength improvements are evident as irradiation increases up to 210 kGy. Irradiated blends exhibit improved tensile strength and elongation at breakage with respect to pure LDPE and EVA. Volume resistivity (VR) and dielectric constant (DC) of the blends were also studied as a function of EVA content, TMPTMA content and radiation dosage. Increasing EVA and TMPTMA content enhances DC and VR values, whereas, increasing irradiation dosage only effects VR values of the blends. The maximum VR value attained in this work corresponds to a radiation dosage of 170 kGy and a blend comprising of 30 wt% of EVA.
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