Mechanical properties of a thermoplastic adhesive modified with graphene nanoplatelets for automotive applications

The potential use of exfoliated graphite nanoplatelets have been explored in many areas of science and engineering due to its unprecedented chemical, physical and mechanical properties. The interest for the use of this kind of graphene has increased in the car industry sector in the last years, to take advantage of the peculiar properties of this innovative material. As a consequence, among the different use of graphene, we have started to explore its application as active filler for thermoplastic structural adhesives. In particular we are studying the possibility of taking advantage of its electro-magnetic properties in order to melt the adhesive layers used to bond parts made by different materials, by using electromagnetic induction or microwave. In this way, beside the typical advantage of using adhesive as joining technology, the vehicle components can also be easily disassembled with benefits in terms of repairing and recycling at the end-of-life. Although this additional property could be used to melt the adhesive, the addition of fillers in an adhesive matrix lead to an improvement of its mechanical properties. For these reasons in this work we have investigated the changes induced into the mechanical properties of a polyolefin based thermoplastic adhesive, modified with graphene nanoplatelets . Performed Single Lap Joint (SLJ) tests show a significant enhancement of the mechanical properties, in particular the ultimate strength, of the nano-modified adhesive in comparison with those of the pristine adhesive. These obtained results have been also compared with those obtained with the same adhesive modified by addition of ferrite or magnetite particles. Further the joint separation surfaces have been inspected and compared in order to show similarities and differences among the use of the different fillers.