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Comparative study: Oven tests and high-pressure autoclave tests (HPAT) on one commercially available PE-HD material

A polyethylene high density (PE-HD) product has been subjected to a very extensive test program to compare the oven method with the high pressure autoclave test (HPAT) method regarding life time estimation and energy/time demand. Oven tests have been carried out at four temperatures between 85 °C and 100 °C for more than three years and they are still running. After three years, oxidation induc-tion time (OIT) has decreased significantly, but mechanical properties remain unchanged so far. Along-side high-pressure autoclave tests (HPAT) have been performed at various test temperatures between 60 °C and 90 °C and oxygen pressures between 165 kPa and 5,100 kPa in a considerably shorter period of time. The estimation of end-of-life at a service temperature of 40 °C and atmospheric pressure are lying in the range of 220 years to 330 years with calculated activation energies between 90 kJ/mol and 94 kJ/mol. By comparing the energy demand the savings potential of using HPAT method instead of oven ageing is enormous. The HPAT method with approx. 4,600 kWh and 1,100 d test duration in total was much more electrical energy and time saving than the oven method with more than 28,600 kWh and more than 4,500 d test duration. With regard to a reduced test program (already fewer measurements are sufficient) HPAT method with 2,400 kWh (630 d test duration) has an energy saving of about 90% compared with the oven method with more than 22,500 kWh (3,500 d test duration).