Natural weathering effects on white, green, and black HDPE textured GMs

This study investigates the degradation of textured High-Density Polyethene (HDPE) geomembranes (GMs) subjected to natural weathering for 8.5 to 10.5 years. The GMs, denoted as GM-W/B (white and black), GM-G (green) and GM-B (black), had a nominal thickness of 1.00 mm and were manufactured using a flat die process with texture on both surfaces. Standard Oxidation Induction Time (Std-OIT) tests and Thermogravimetric Analysis (TG/DTG) were performed to assess the antioxidant depletion and thermal decomposition. Additionally, degradation due to Ultraviolet (UV) radiation and environmental agents was assessed through retained physical and mechanical properties, including the Melt Flow Index (MFI) measured under various loading conditions. Antioxidant depletion and TG/DTG analyses indicated that environmental exposure compromised the thermal stability of these GMs. Among the tested GMs, GM-W/B exhibited the greatest reduction in both Std-OIT and MFI, followed by GM-G and GM-B, suggesting a direct correlation between these properties. While GM-B appeared to be still in the antioxidant depletion stage (Stage I), GM-W/B and GM-G showed signs of degradation beyond Stage I. This study provides insights into the degradation of textured HDPE GMs in the face of weathering exposure effects and the durability of colored HDPE GMs.