GraPoly: Enhancement of Conductive Graphite-Polymer Nanocomposites
The objective of the research project is to improve electrical and thermal properties of polymeric matrix composite materials loaded with graphite and nanographite.

The particular characteristics which can be obtained thanks to these nanoloads have been used to develop a new family of nano composites, while at the same time analysing specific related applications. The project has provided for the manufacture and mixing of various types of new nanoinclusions with polymeric thermoplastics and thermohardened matrices. Some of these samples are now being considered for an industrial scale-up.

Surface treatments for the improvement of the interaction between the matrix and the inclusion have also been considered in detail. Moreover, the project has provided for the construction of new models of conductivity for polymeric nanocomposites: the typical models for conductive composites with conventional inclusions do not, in fact, work properly when applied to nanometric inclusions. To meet such needs, a formulation of conductivity based on electronic interparticle tunnelling was introduced.

The synergistic application of a theoretical approach with a series of heavy numerical simulations has allowed the formulation of a model of conductivity in which particles dispersed in the matrix form a network of interconnected objects through tunnelling, which induces an insulation-conductor transition capable of reproducing the curves of conductivity according to the content of nano dispersion found experimentally.

Several imaging techniques were also used to analyse the morphologies of composites, including the innovative x-ray phase contrast tomography . Thanks to the combined use of such innovative techniques with the theoretical approach described above, it was possible to consider the case of graphite-polymer composites, the principal objective of the project, in greater detail, introducing a simple model of conductivity capable of accounting for some of the characteristics of these experimentally-observed materials.

The research – funded by the Agency for the Promotion of Innovation CTI and directed by Andrea Danani of the Department of Technology Innovation – was carried out in collaboration with the Ecole Polytechnique Fédérale de Lausanne (Laboratoire de Production Microtechnique) and TIMCAL SA, the world leader in the production of powdered graphite and highly specialized carbon.

Director: Andrea Danani
Department: Department of Technology Innovation
Research Units: CIM Institute for Sustainable Innovation
Duration of the Project: 2007-2009
Funding Organisation: CTI