Accelerated Hydrothermal Aging and Degradation Mechanism of PE100 Butt-Fusion Welded Joint.

High-density polyethylene (HDPE) pipelines are extensively utilized in energy transportation in the ocean. However, long-term exposure to water can alter the performance of HDPE, potentially leading to pipeline accidents. This study focuses on simulating the aging characteristics of PE100 polyethylene pipeline butt-fusion welded joints (B-FWJs) in water using hydrothermal accelerated aging experiments at various temperature gradients. The performance of the B-FWJ after hydrothermal aging was characterized using scanning electron microscopy (SEM), oxidation induction time (OIT), attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy, and mechanical testing. Furthermore, this study analyzed the performance characteristics and changes in the micro-molecular chains of an HDPE B-FWJ pipeline following hydrothermal aging. An investigation was conducted into the effects of hydrothermal aging temperature and duration on the physical and chemical characteristics of HDPE B-FWJ, and the aging mechanism under hydrothermal aging conditions was explored. The results indicate that increasing hydrothermal aging temperature leads to a more significant decrease in the mechanical properties of the B-FWJ. These findings contribute to understanding the aging behavior of PE100 pipelines in the joint section and offer insights to mitigate the risks associated with the aging of and damage to B-FWJ pipelines in the ocean.