Aeronautic structures need to meet two criteria: high performance and lightweight. In this contest, graphene-based composites may play a game-changing impact in terms of performance and efficiency because of the electrical and other unique physical properties of graphene that could allow smart integration of lightning strike protection, flame retardancy, impact resistance and other functions combined in new multifunctional structures for use in the aviation industry. Besides, the necessity to improve local conductivity measurements led to the development of techniques for nanometerscale electrical characterizations. Our recent research has focused on developing high performance polymer nanocomposites, with the benefit of carboxylated partially exfoliated graphite (CpEG) and flame retardant glycidyl polyhedral oligomeric silsesquioxane (GPOSS) nanoparticles, to achieve a novel multifunctional epoxy resin. This multifunctional system has been specially designed so as to meet specific aeronautical requirements through tailored properties by identifying the best strategy for improving its thermal, fire resistance and electrical conductivity. This paper presents the first successful attempt to obtain a conductivity mapping of a new multifunctional epoxy resin, by tunneling AFM (TUNA) setup in order to characterize ultra-low currents in the range between 80 fA to 120 pA. In this technique, that uses a conductive AFM probe in contact mode, the sensor signal is the electric current between the AFM tip and the conductive sample for an applied DC bias. This non-contact technique help in carrying out various non-destructive measurements on electrical conductive nanoparticles to obtain point measurement scan of the sample topography and its corresponding electrical data. In particular, this paper focus on electrical characterization at nanoscale level using Tunneling AFM (TUNA) and flammability behavior of a new multifunctional nanocomposite. It is worth noting that the samples have been analyzed by AFM-TUNA without undergoing any prior treatment with silver paste that is usually used to create electrical contacts to the ground, proving undoubtedly that they are intrinsically conductive. The increase of limiting oxygen index (LOI) value and the decrease of the peak of heat release rate (PHRR) value, observed when GPOSS is used, together with the high electrical and mechanical properties and good thermostability imparted by selfassembly blocks of CpEG nanofiller, confirm the possibility of creating a true multifunctional composite.
Nanoscale Electrical Characterization by Tunneling AFM (TUNA) and Flammability Behaviour of a New Aeronautical Multifunctional Graphene/POSS Epoxy Resin
RAIMONDO, MARIALUIGIA;GUADAGNO, Liberata;NADDEO, Carlo;SPERANZA, Vito;
2017-01-01
Abstract
Aeronautic structures need to meet two criteria: high performance and lightweight. In this contest, graphene-based composites may play a game-changing impact in terms of performance and efficiency because of the electrical and other unique physical properties of graphene that could allow smart integration of lightning strike protection, flame retardancy, impact resistance and other functions combined in new multifunctional structures for use in the aviation industry. Besides, the necessity to improve local conductivity measurements led to the development of techniques for nanometerscale electrical characterizations. Our recent research has focused on developing high performance polymer nanocomposites, with the benefit of carboxylated partially exfoliated graphite (CpEG) and flame retardant glycidyl polyhedral oligomeric silsesquioxane (GPOSS) nanoparticles, to achieve a novel multifunctional epoxy resin. This multifunctional system has been specially designed so as to meet specific aeronautical requirements through tailored properties by identifying the best strategy for improving its thermal, fire resistance and electrical conductivity. This paper presents the first successful attempt to obtain a conductivity mapping of a new multifunctional epoxy resin, by tunneling AFM (TUNA) setup in order to characterize ultra-low currents in the range between 80 fA to 120 pA. In this technique, that uses a conductive AFM probe in contact mode, the sensor signal is the electric current between the AFM tip and the conductive sample for an applied DC bias. This non-contact technique help in carrying out various non-destructive measurements on electrical conductive nanoparticles to obtain point measurement scan of the sample topography and its corresponding electrical data. In particular, this paper focus on electrical characterization at nanoscale level using Tunneling AFM (TUNA) and flammability behavior of a new multifunctional nanocomposite. It is worth noting that the samples have been analyzed by AFM-TUNA without undergoing any prior treatment with silver paste that is usually used to create electrical contacts to the ground, proving undoubtedly that they are intrinsically conductive. The increase of limiting oxygen index (LOI) value and the decrease of the peak of heat release rate (PHRR) value, observed when GPOSS is used, together with the high electrical and mechanical properties and good thermostability imparted by selfassembly blocks of CpEG nanofiller, confirm the possibility of creating a true multifunctional composite.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
