Influence of accelerated aging (temperature and acid attack) on the mechanical properties, structural, and morphological characteristics of high-density polyethylene sewer pipes

Abstract

This article analyzes the aging effect of HDPE sewer pipes when exposed to sulfuric acid at different temperatures. The mechanical properties, structural and morphological changes were evaluated. Results showed an impressive environmental degradation of HDPE. The tensile test showed that with a well-correlated increase in immersion time and higher temperatures, the elongation and ultimate stress of HDPE decreased. At 60 °C, the elongation at break indicated, at every time interval, an abrupt drop and a simultaneous loss of ductility. The micro-structural FTIR absorptions at 719–730, 1462–1472, 2848, 2916 and 3400 cm–1 were detected and compared using the spectrum of an unaged HDPE. The modification of the mechanical properties seems to correlate well with the structural observations obtained from the scanning electron micrographs. Eventually, it was discovered, via thermal aging studies, that the combination of temperature and sulfuric acid appears to be a major factor in high-density polyethylene breakdown.