Influence characteristics of water penetration on fibre‐reinforced polymer/rigid polyurethane foam interface of the composite cross‐arm considering natural ageing

Abstract

Fibre‐reinforced polymer (FRP)/rigid polyurethane foam (RPUF) interface is susceptible to moisture intrusion in addition to natural ageing during operation. This study investigated the influence of moisture intrusion on the FRP/RPUF interface under natural ageing using experiments and molecular dynamics (MD) simulations. Water absorption, shear strength, and leakage current tests were used to clarify the changes in the interface performance. The degradation mechanism of moisture intrusion at the interface under natural ageing was revealed by MD simulation and micro‐characterisation. The results show that the natural ageing of interfacial materials will slightly reduce the quality of the interface but will reduce the water resistance of the material and promote the process of water intrusion into the interface. In addition, water mainly invades the interface through RPUF. After water penetration, the interfacial bonding strength and insulation performance significantly decreased. Plasticisation and hydrolysis of interfacial materials are the main reasons for decreased interfacial adhesion. Hydrolysis can cause irreversible damage to the interface, increasing interface defects and water absorption. The vicious cycle of material hydrolysis is the ultimate cause of interfacial debonding. The polar molecules produced by this process and the water absorbed by the interface caused the degradation of the interface insulation performance.