Effect of temperature and water penetration on the interfacial bond between epoxy resin and glass fiber: A molecular dynamics study

According to the hydrothermal working environment, accidents related to composite insulator string rupture are frequently encountered in transmission line, which cause serious hazard to the stability of power system. The interface between epoxy resin matrix and glass fiber fillers is one of the microscopic interfaces in the insulator core rod. The adhesion strength of that interface has important implications for the overall mechanical properties of the core rod. This study aims to analyze the influence of temperature and water intrusion on the interfacial adhesions. By molecular dynamics (MD) simulation, a molecular modelling of epoxy resin / glass fiber interface under water molecular environment was established. The mechanism of deterioration is indicated through the interfacial binding energy, ester number, radial distribution function (RDF) and H-bonds number of the interface model. It was found that when the temperature increased to a certain level, the water molecules were easy to migrate to the interface through the holes in the epoxy resin. When the temperature reaches 373 K, the epoxy resin occurs hydrolysis reaction, which will promote the cracking of epoxy resin. Meanwhile, water molecules migrated to the interface can hinder the formation of hydrogen bonds between epoxy resin and glass fiber. Under the synergistic effect of the above factors, water gradually causes the degradation of epoxy resin / glass fiber interface.