Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector
Dielectric, low?frequency noise and mechanical properties of hybrid carbon nanotubes/graphene nanoplatelets epoxy composites
Frequency dependence of the dielectric permittivity and electrical conductivity in the 20 Hz–1 MHz frequency range.This study analyzes the electrical, microwave (26–37?GHz), low?frequency (20?Hz–10?kHz) noise, and mechanical properties of epoxy hybrid composites filled with multi?walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GNP). The system's percolation threshold was around 0.25?vol.% MWCNT, while the electromagnetic properties were almost independent of GNP concentration. The composites are shown to be suitable for electromagnetic shielding in the 26–37?GHz range, with microwave absorption increasing as the total nanocarbon concentration rises. The electrical transport in these composites is governed by one?dimensional Mott hopping at low temperatures (below 245?K) and redistribution effects above room temperature. The low?frequency voltage noise spectra of the composites are predominant of the 1/f component, with noise spectral density proportional to Ub, where the exponent b is close to 2, indicating noise caused by resistance fluctuations. The optimal electromagnetic properties are near 0.5?vol.% MWCNT and 0.25?vol.% GNP concentrations. The tensile elastic modulus and yield strength showed the highest increases at 0.25/0.25 loading, with gains of 40.43% and 16.77%, respectively, compared to neat epoxy. Fracture toughness and energy release rate increased with adding 0.25?vol.% GNP, while Charpy impact strength improved with higher MWCNT loading.HighlightsPercolation threshold in hybrid MWCNT/GNP composites is close to 0.25 vol.% MWCNTLow?frequency voltage noise spectra of the composites are 1/f type
» Publication Date: 23/10/2024
This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº 768737
