Evaluation of Degradation of Structural Adhesive Joints in Functional Automotive Applications

Adhesive joints used in automobiles are subjected to very adverse operating conditions. Under these conditions, deterioration of the adhesive bond can be produced due to degradation both environmental and temperature, which leads to a decrease of the mechanical properties of the assembly over time. The present study analyzes the degradation experienced by adhesive joints of composite with aluminum, with two different adhesives (an epoxy and a polyurethane), when these are subjected, on one hand, a prolonged environmental exposure and, moreover, aging caused by high temperature and immersion in engine oil. Test results indicate that epoxy adhesive has better mechanical behavior than the polyurethane when the stays are prolonged weathering. Also, the epoxy adhesive also has good technical performance under the joint action of immersion in oil and heat, since this adhesive improves flexibility, and resistance to bending and tensile not experience significant changes during the 128 hours of the test.