A more reliable detergent for constant load experiments on polyethylene

Testing polyethylene materials for stress cracking resistance at elevated temperatures in the presence of a detergent solution is relatively popular. The detergents used for these tests are—to our knowledge—only of the ethoxylated nonylphenol type (trade names: Igepal, Antharox, Arkopal). Extensive investigations of solutions of these nonionic detergents used at 80 °C have shown that they are very susceptible to oxidation. Oxidation has already started after about one day at 80 °C and leads to erroneous failure times of polyethylene test bars exposed to the detergent and to an unacceptably large scatter in the data.

An alternative anionic alkylbenzene sulphonate (ABS) detergent has been tested which, when dissolved in drinking water, produces reproducible failure times of welded polyethylene samples, if the age of the detergent solution does not exceed about 2000 h at 80 °C.