Development Of Smart Nanocomposites For High-Performance Engineering Applications

Abstract

Smart nanocomposites integrate structural integrity with inbuilt functions like damage detection, strain sensing and self-healing. A hybrid epoxy nanocomposite comprising multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) in a 1:1 mass ratio and loadings between 0.25 and 2.0 wt% has been developed. Solvent assisted ultrasonication process followed by three-roll milling and thermal curing was used to prepare composites. Dispersion characteristic, mechanical, thermal, electrical and piezoresistive properties were characterized. The 1.0 wt% hybrid composite showed the best structural balance, with tensile strength rising from 62.4 to 89.3 MPa (+43%), Young's modulus from 2.85 to 3.78 GPa (+33%), and fracture toughness from 0.62 to 1.12 MPa·m^0.5 (+81%). An electrical percolation threshold of about 0.32 wt% was determined and the electrical conductivity was measured at 0.21 S/m at 1.0 wt%. This loading produced a 14.6 gauge factor for the material and a good cyclic stability. Thermal conductivity increased by 324% at 2.0 wt% and the thermal stability was improved. Agglomeration caused a decrease in mechanical gains beyond 1.0 wt%, but did not cause any change in conductivity. Based on the results, the optimal window of 0.75–1.25 wt% is recommended for the use of the material in multifunctional engineering applications, such as aerospace, automotive, and civil structures health monitoring.