Preparation and mechanical properties of graphite nanosheet/nylon 610 nanocomposites using graphite nanosheets treated with supercritical water

AbstractIn this study, water at high temperature (175°C) and in vacuum state (−1 bar) is applied to graphite nanosheets to enhance surface activity through the formation of oxygen functionalities via supercritical water treatment. The nylon 610 nanocomposites (with treated or untreated nanosheets as nanofillers) was then synthesized using interfacial polymerization. X‐ray diffraction (XRD) analysis showed that the water treatment had not altered the crystal structure of the graphite nanosheets. On average, the Young's modulus and tensile strength of the nanocomposites are larger than the pure nylon 610 created, with the highest Young's modulus and tensile strength obtained being 137.44 MPa and 930.49 kPa, respectively. The tensile strength of treated nanosheets/nylon nanocomposites generally decreased with increasing wt%; while, that of untreated nanosheets/nylon nanocomposites increased with increasing wt%. This enhancement in mechanical properties can be attributed to the functionalization of graphite nanosheets, which may yield a slight oxidation on its surface, allowing for stronger interaction between the nylon 610 matrix and the nanosheets. Fourier transform infrared (FTIR) spectra also showed the presence of hydrogen bonding between the carbon nanofillers and the polymer matrix through the appearance of amide bands. Furthermore, scanning electron microscopy (SEM) showed that at higher wt%, aggregation will occur, which may lead to a weakening in physical properties. Nevertheless, this improvement in mechanical properties when compared with pure nylon 610 can be attributed to the intact structure of the nanosheets and the chemical bonding between the nanofillers and nylon 610.