Study on the physiochemical behavior of PE and epoxy composites immersed in an NaOH solution for a long period

Abstract

A seawater electrolyzer solution has high alkalinity owing to the presence of scale-like hydroxide compounds, Ca(OH)2, and Mg(OH)2 generated from a dimensionally stable anode during electrolysis. This study proposes four different types of composite materials to replace the existing ballast piping materials that are vulnerable to high alkalinity. To this end, composite specimens were prepared and immersed in an NaOH solution for 720 h. Furthermore, their suitability as ballast pipe materials was confirmed through a physical property analysis of the immersed specimens. The results show that all four types of composite specimens deteriorated, but they had different interfacial bonding mechanisms. For specimens with low interfacial bond strength between fibers and resins, the deterioration initiated and propagated from the surface and the internal penetration of the NaOH solution occurred rapidly, resulting in the rapid deterioration of their physical properties. The mechanisms of good and bad interfacial bonding between fibers and resins were determined based on the interfacial bonding force. Thus, this study will help understand the deterioration mechanisms of composite materials immersed in chemical solutions such as NaOH or acid in the future.