Study of the mechanical, dielectric, and thermal properties of annealed modified nanodiamond/epoxy composites

Electrical properties of Nanodiamond (NDs) with individual diameters of ∼5 nm are important for many engineering applications and drawing significant attention of the current research community. In this paper, we reported a systematic approach to remove sp² carbon content from NDs particles by annealing method to enhance the interfacial molecular bonding between reinforcement and matrix. X-ray Diffraction (XRD) and Fourier Transform Infra-Red Spectrophotometer (FTIR) studies revealed that annealing of NDs occurs at 450 °C, indicating that the decrease in resistivity is based on the sp²/sp³ carbon ratio of NDs. Thus, it is interesting to study the properties of annealed NDs/epoxy nanocomposites with small filler concentrations varying from 0.1 wt% to 0.5 wt%. In this paper, the Dielectric properties (dielectric constant and dielectric strength), thermal conductivity, impact strength, micro-hardness, and compressive behaviour of NDs/epoxy nanocomposites were investigated. Dispersion of NDs at very low concentration was ensured with the help of UV–vis–NIR absorbance spectra analysis. It was observed that the dielectric constant (ε′) was enhanced with NDs loading and reached an optimum value at 0.3 wt% of the loading of NDs whereas the dielectric strength showed a reverse pattern. The thermal conductivity and Izod impact strength showed maximum improvement of 21% and 104.0% respectively at 0.3 wt% NDs loading. (paper)