The effect of different stabilizers on the thermostability of electron beam crosslinked polyethylene in hot water

Abstract

Plastic pipes owing to their flexibility, great lengths, easier handling and absence of corrosion have been used for hot-water installations. Crosslinked high-density polyethylene is one of the best materials, being used for this purpose. The useful lifetime of unstabilized polyethylene is predicted to vary from a few months in hot water (30–40 °C) to almost two years in cool water (0–10 °C). Polyethylene was mixed with different types of stabilizers, in order to increase its durability. The samples were irradiated at 100–150 kGy. The amount of gel fraction and the changes in mechanical properties were measured. Irradiated samples were immersed in hot water for 1000 h. The thermostability of the specimens and the existence of antioxidants were measured by the induction time technique using differential scanning calorimetry at different time intervals. Furthermore, the changes in chemical structure and mechanical properties of the samples during their immersion in hot water were determined.