Salvatore Russo

Influence of carbon nanoparticles/epoxy matrix interaction on mechanical, electrical and transport properties of structural advanced materials

The focus of this study is to design new nano-modified epoxy formulations using carbon nanofillers, such as carbon nanotubes, carbon nanofibers and graphene-based nanoparticles (CpEG), that reduce the moisture content and provide additional functional performance. The chemical structure of epoxy mixture, using a non-stoichiometric amount of hardener, exhibits unique properties in regard to the water sorption for which the equilibrium concentration of water (C eq) is reduced up to a maximum of 30%. This result, which is very relevant for several industrial applications (aeronautical, shipbuilding industries, wind turbine blades, etc), is due to a strong reduction of the polar groups and/or sites responsible to bond water molecules. All nanofillers are responsible of a second phase at lower glass transition temperature (Tg). Compared with other carbon nanofillers, functionalized graphene-based nanoparticles exhibit the best performance in the multifunctionality. The lowest moisture content, the high performance in the mechanical properties, the low electrical percolation threshold (EPT) have been all ascribed to particular arrangements of the functionalized graphene sheets embedded in the polymeric matrix. Exfoliation degree and edge carboxylated groups are responsible of self-assembled architectures which entrap part of the resin fraction hindering the interaction of water molecules with the polar sites of the resin, also favouring the EPT paths and the attractive/covalent interactions with the matrix.

Thermal Degradation and fire properties of epoxy modified resins

The flammability of the resin is a major limitation in the aeronautic applications where new developed materials for primary and secondary structures must fulfill special regulation in order to demonstrate that their level of fire safety is equivalent to a conventional transport (aluminum) material. In this paper, the attention is focused on the thermal properties and the fire behavior of TGMDA based epoxy resins in which carbon nanotubes and POSS have been dispersed at nanometric or molecular level. The effect of the hardener, the diluent and the nanoparticles on the thermal properties has been investigated. Thermogravimetric data have been modeled according to the Coats and Redfen equations which provide a fast method for the determination of the kinetics of thermal degradation of polymers. The char yield has been used as criteria for evaluating limiting oxygen index (LOI) of the resin in accordance with Van Krevelen and Hoftyzer equation and the results have been compared with the experimental LOI dataThe flammability of the resin is a major limitation in the aeronautic applications where new developed materials for primary and secondary structures must fulfill special regulation in order to demonstrate that their level of fire safety is equivalent to a conventional transport (aluminum) material. In this paper, the attention is focused on the thermal properties and the fire behavior of TGMDA based epoxy resins in which carbon nanotubes and POSS have been dispersed at nanometric or molecular level. The effect of the hardener, the diluent and the nanoparticles on the thermal properties has been investigated. Thermogravimetric data have been modeled according to the Coats and Redfen equations which provide a fast method for the determination of the kinetics of thermal degradation of polymers. The char yield has been used as criteria for evaluating limiting oxygen index (LOI) of the resin in accordance with Van Krevelen and Hoftyzer equation and the results have been compared with the experimental LOI data