Peel behavior of polyurethane/Monel 400 interface under load in saline water

ABSTRACT This study investigates the coupling effects of saline water and cable weight on the adhesive energy of polyurethane/Monel 400 interface using a dead weight peel test. Cables play a crucial role in naval structures serving as a central nervous system. The cables and their connectors are generally molded, encapsulated, or potted with polyurethanes to ensure that they are insulated and waterproof. During service, exposure of some of these cables and their connectors to the marine environment results in the premature failure of the polyurethane/metal interfaces of connectors. Three sets of experiments were carried out to better understand this phenomenon: an initial 90° fixed arm peel test to determine the strength of the interface, a hanging weight peel test in saline water at an elevated temperature to determine the effects of weight variation and saline water degradation, and a dead weight peel test at varying saline water temperatures to determine the acceleration factor. According to the findings, no peel was recorded in the peel experiments conducted in air indicating that the strength of the interface is higher than that of the peel arm. In the dead weight peel tests, increasing the masses of the hanging weights increased the peel velocity. Additionally, for low peel velocities, a linear relationship was observed between adhesive energy and peel velocity. Furthermore, a more cohesive primer failure was observed at the end of the peel process, indicating that peel velocity increased with longer exposure to saline water.