Reinforcement effect of acid modified nanodiamond in epoxy matrix for enhanced mechanical and electromagnetic properties

•Acid modified epoxy/DND nanocomposite, synthesis and characterizations.•Exploration of the mechanical and electromagnetic attenuation of epoxy/DND nanocomposites.•Maximum enhancements of mechanical properties at 0.2 wt% DND loading.•Maximum electromagnetic attenuation properties of the epoxy/DND nanocomposites at 0.4 wt% DND loading.

We applied acid treatment for the surface modification of detonation nanodiamond (DND) powder by minimizing their surface energy to overcome agglomeration and improve dispersion of DNDs. Different concentrations of acid modified DND in 828 epoxy matrix were fabricated to check their mechanical and electromagnetic properties. Mechanical properties were checked in terms of ultimate tensile strength (UTS), toughness, energy to break, percent strain break and Young's modulus while electromagnetic shielding properties were studied in frequency range of 11-17 GHz. To analyze electrical and magnetic properties of the nanocomposites, relative permittivity and permeability tests were performed. Excellent interactions among acid modified DND and epoxy resin was observed due to carboxyl and hydroxyl functional groups that results in the formation of efficient load transfer interface, which in turn enhance the mechanical and electromagnetic properties of epoxy nanocomposites. During investigation it was observed that mechanical properties and relative permittivity showed enhancements when, 0.2 wt% acid modified DND were used as a nano-filler, while on further increment of modified DND these properties start decreasing. Unlike this, the relative permeability, reflection and transmission loss values were increased with the increase of acid modified DND content.

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