Functionalization of adhesives and composite matrix by micro and nanoparticle addition

The use of nano and microfillers in research and industrial areas have been increasing in recent decades. In material industry especially, the combination of specific nano and microparticles properties has been studying since they can offer a great contribution to the resolution of tough issues. One of these issues is the possibility to disassemble components for repairing, recycling or avoiding waste when errors occur in manufacturing processes. The disassembly of mechanical component is still an open issue and there are many technical problems that are involved in this process. For example, the possibility to have a clean surface of the separated component after the disassembly or the possibility to introduce damages to other linked components. This dissertation investigates the possibility to disassemble a hot-melt adhesive, used in automotive industries to join plastic components, by embedding iron nanoparticles, Fe3O4, that are sensitive to electromagnetic induction. This peculiarity makes the modified adhesives able to melt when an electromagnetic field is oriented on it and so the joint separation is possible. The mechanical and physical properties of these nanomodified adhesives, with different particles concentrations of iron oxide, were studied and compared with the pristine adhesive. This correlation was necessary in order to assess the possibility to use these modified adhesives in the vehicle assemblies since the pristine adhesive is already used by some car manufacturers for internal and external components. Separation tests of plastic joints were evaluated and the most sensitive factors were stated and analysed. The shape of the inductor coil, the diameter of the pipe coil, the frequency of the applied magnetic field and the applied current were found to be influencing factors of the induction heating process. The possibility to use cheaper particles, iron microparticles coupled with electromagnetic induction, together with the possibility to bond composite, glass fibre-reinforced plastics (GFRP), substrates were assessed as well. Composite components have been replacing many structural and non-structural components in automotive design in order to reduce the vehicle weight. The opportunity to disassemble adhesive with graphene nanoparticles embedded in the same hot-melt adhesive and coupled with microwave was assessed as well. The heating of this particles is possible by means of the π electron mechanism In recent decades, researchers and industries have been also investigating the possibility to make a material electrically conductive. In this PhD dissertation, the possibility to make a structural epoxy resin electrically conductive have been discussed as well. In order to make the material electrically conductive, different coatings of glass spheres with conductive GnPs were tried, as well, but in these cases, the coating results was not satisfactory. For these reasons the chosen filler concentration for these tests was set at 1% (volume fraction) for the conductive filler and 30% (volume fraction) for the hollow glass spheres. These were the maximum concentration that it was possible to embed in the epoxy matrix in order to obtain an easy processability of the material. The modified epoxy resins were not conductive they showed interesting mechanical properties especially under compressive load.