Effect of nanodiamond particles on the structure, mechanical, and thermal properties of polymer embedded ND/PMMA composites

Nanodiamonds (NDs), the allotropic carbon nanomaterials with nanosize, durable inert core, adjustable surface morphology, high thermal constancy, and super mechanical performances, possess the characteristics of promising reinforcement materials for various technological applications. However, ND particles hold a vigorous propensity to aggregate in liquid media, obstructing their implementation in mechanical and thermal sciences. This aggregation is caused by high surface to volume ratio. By reducing the surface energy and lowering cluster formation, the mechanical and thermal properties of NDs can be polished. Herein, we report on the covalent functionalization of NDs with amine moiety through ball milling method. Their dispersion was checked in ethanol and polymethyl methacrylate (PMMA polymer) against nonfunctionalized NDs. The dispersive behavior showed that ball mill functionalized NDs produced preferably stable aqueous dispersions in ethanol media. Furthermore, 0.1, 0.2, and 0.4 wt% ND/PMMA composites were synthesized, and their mechanical and thermal behaviors were studied in terms of hardness, compression, Young's modulus, flexural strength, tensile strength, and thermogravimetric analysis (TGA). Results revealed that the composites containing 0.2 wt% functionalized ND loaded with PMMA matrix showed outstanding mechanical and thermal performances indicating that 0.2 wt% is the optimum amount for achieving excellent outcomes.