Nanocompuestos basados en materiales grafénicos para aplicaciones de ingeniería

Abstract

This doctoral dissertation has been presented in the form of thesis by publication. Engineering has evolved over the centuries inseparably linked to the research and development of materials. So much so that the vast majority of engineering systems that have constituted a disruptive breakthrough or even a paradigm shift have been made possible by the discovery of a new material, to the extent that some ages are named after materials, such as the age of iron. Composite materials, and more recently, nanomaterials and nanocomposites, are families of materials whose discovery and development have made possible the emergence of highly innovative engineering applications. A nanocomposite material is a composite material that has at least one nanomaterial among its components. Of all the nanomaterials investigated for the formation of nanocomposites, Graphene is the one that generates the most excitement in industry due to its unique properties. Graphene is a two-dimensional allotropic form of hexagonal crystalline carbon, whose derivatives form the family of graphene materials. Graphene materials are being widely investigated as doping agents for a multitude of materials because they endow the resulting nanocomposites with properties that enable the design of highly innovative engineering systems. This doctoral thesis, presented as a compendium of publications and patents, describes the research work carried out on the development of nanocomposites based on graphene materials for engineering applications. In the first article, “Urethane-acrylate/aramid nanocomposites based on graphenic materials, A comparative study of their mechanical properties”, a comparative study of the mechanical properties of different polymer matrix nanocomposites doped with graphenic materials (Graphene nanoplates, reduced graphene oxide and pristine few-layer graphene) was carried out. Specifically, the effect that doping with these three types of graphene materials has on the tensile, bending and Charpy impact properties of the nanocomposites obtained has been studied. The results showed that nanocomposites doped with pristine few-layer graphene had the greatest increase in all the mechanical properties evaluated, achieving significant improvements compared to undoped laminates. This nanocomposites exhibited low density, a high fibre-to-resin ratio, homogeneous dispersion of the nanoreinforcement and easy scalability. These results highlight the potential of using graphene-doped urethane-acrylate/aramid nanocomposites in applications requiring improved mechanical properties. The second article, “Ibuprofen removal by graphene oxide and reduced graphene oxide coated polysulfone nanofiltration membranes”, analyses the effect that the modification of polysulfone nanofiltration membranes by graphene oxide and reduced graphene oxide has on the removal of the emerging pollutant ibuprofen. A study of the morphology and composition of the modified and unmodified membranes, as well as their water permeability and permeate fluxes and rejection coefficients at different ibuprofen concentrations and working pressures, was carried out. The results showed that membranes modified with graphene oxide and reduced graphene oxide have lower water permeabilities and permeate fluxes, and higher ibuprofen rejection coefficients than unmodified membranes, with the highest ibuprofen rejection coefficient obtained in membranes modified with reduced graphene oxide. The first patent, “Cement mortars doped with graphitic and graphenic nanomaterials with thermoelectric conductivity”, relates to the design and development of the formulation and process for the preparation of a ceramic matrix nanocomposite material doped with graphitic and graphenic materials that is thermally and electrically conductive. A preferred formulation and preparation procedure for obtaining rigid plates and coatings with a thermal conductivity ≥0.5 W/m·K and an electrical resistivity ≤9·10−2 Ω·m are also described. The invention also refers to the final set cement mortar product obtained with the aforementioned formulation by means of the described procedure.The second patent (application), “Polymer matrix coating doped with graphene nanomaterials resistant to corrosion and adhesion of marine life”, relates to the design and development of the formulation and process for the preparation of a polymer matrix nanocomposite material based on a thermosetting urethane-acrylate resin doped with graphene nanomaterials and resistant to corrosion and adhesion of marine life. A preferred formulation and preparation procedure and a particular embodiment of the invention for improving the nanocomposite properties are detailed. A comparative analysis has been carried out between the properties of the developed nanocomposite and a commercial coating in a relevant environment, such as the sewage wells of the port of Valencia (Spain). The results obtained show that the nanocomposite of the invention has a high resistance to corrosion and adhesion of marine life.