Unraveling the effect of carbon nanotubes on the dielectric and mechanical properties of inorganic silica rich stone waste nanocomposites

Abstract

For the first time, a high performance carbon nanotube (CNT) reinforcement-stone waste polymer nanocomposite was fabricated using an epoxy matrix via the compressive molding route. The morphological, mineralogical, and functional group presented by the pristine stone waste and CNT-reinforced stone polymer nanocomposites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformed infrared spectroscopy. Strong interfacial bonding between stone waste, carbon nanotubes, and epoxy polymer was achieved through the polar dimethylformamide (DMF) solvent and through the high energy ball milling process. The dielectric constant drastically increased with an increase in CNTs in the stone waste-epoxy matrix. Very high dielectric constant up to 1800 was achieved for the 0.2 (wt%) CNT-filled stone waste sample, whereas the pristine stone composite exhibits a low dielectric constant of 26. It was found that the stone waste nanocomposites with a higher CNT content produced a lower dielectric constant. CNT-filled nanocomposites showed high flexural strength and tensile strength of 77 MPa and 20.78 MPa, respectively, for the 0.2% filled CNT nanocomposites. However, at high filler concentrations, both flexural and tensile strength decreased. The results were analyzed in terms of interfacial bonding, polar solvent, and sudden increase in the polarization, improved bonding, and agglomeration tendency of the CNTs.