A survey of methods for the detection of thermal oxidation in high-density polyethylene pipes

Seven methods for the detection of thermal oxidation of the inner wall surface of high-density polyethylene (HDPE) pipes are presented. The methods presented include infrared spectroscopy, polarized light microscopy, differential scanning calorimetry, scanning electron microscopy, gloss measurements and uniaxial creep tests. These tests have been developed on the basis of earlier reported data for a large number of PE pipes. The tests are compared with each other and with the internal pressurizing test with respect to reliability of results, the time taken to determine whether or not a pipe is oxidized, the experimental difficulties, costs, etc.