Nano‐mechanical approach to study the behavior of annealed nanodiamond reinforced epoxy nanocomposites

Abstract Nanodiamonds (NDs) are potential fillers that provide excellent mechanical and multifunctional capabilities. The growing interest in using NDs in a variety of fields has prompted researchers to use NDs to prepare various structural composites. In this work, ND surface modification was performed by a physical process as a systematic approach to remove the sp² carbon content and noncarboneous particles from pristine NDs. The nanohardness and viscoelastic response of modified NDs incorporated with the epoxy matrix were further investigated. The surface morphology and crystalline nature of NDs/epoxy nanocomposites were investigated by scanning electron microscope, transmission electron microscopy, and x‐ray diffraction. Nanoindentation and nano‐dynamic mechanical analysis (DMA) tests were conducted on different composites with 0–0.5 wt% filler variations. The nanohardness and nano‐DMA of various composites were performed at two different loads (5 and 10 mN) in a frequency range of 10–250 Hz. The maximum improvement in the young's modulus was 79% and 52% with the 5 and 10 mN loads, respectively, corresponding to 0.3 wt% filler loading. The storage modulus and loss modulus values increased with the ND concentration in epoxy composites for 10 mN loads compared to 5 mN loads. From the nano‐DMA study, a higher phase lag of the tan δ curve was obtained for 5 and 10 mN loads, with larger tan δ values for NDs nanofiller‐loaded composites compared to neat epoxy. When compared to the 5 mN load, the tan δ value for the 10 mN load increased by 0.3 wt%. Thus, these composites can be used for automobiles and aerospace applications.