Assessing the weathering-induced degradation on the structural integrity of high-density polyethylene

Abstract

Marine plastic pollution is a growing environmental concern, with plastic debris in the ocean having negative impacts on marine life and human health. One of the major challenges in addressing this problem is the slow degradation rate of plastics in the marine environment. In this study, the degradation of high-density polyethylene (HDPE), being extremely common in marine debris, is investigated when exposed to either (a) marine or (b) atmospheric environmental exposure. The weathering effects for this type of plastic were examined through ultraviolet spectrophotometer and tensile investigations. A chain-breaking activity in the microstructure of the weathered HDPE specimens was revealed. During the investigated eight (8) months of atmospheric and sea weathering, an approximate 10 % and 6 % decrease in ultimate tensile strength σUTS was noticed for the two different environments, respectively. Higher decrease was noticed for the respective elastic modulus E (Young’s modulus) that was approximate 23 % and 21 %, respectively. Based on the available experimental test results, a linear decrease rate equation of all the investigated mechanical properties was proposed, to give valuable information regarding the residual tensile mechanical properties of HDPE after weathering exposure.