18. Superior Damping of Hybrid Carbon Fiber Composites Grafted by ZnO Nanorods

The elevated specific strength of fiber reinforced plastics (FRP) is the prominent drive for their ever-growing applications. Their inadequate vibrational damping properties prevent them from replacing conventional metal alloys for certain structural applications. In this study we attempt to utilize a low temperature hydrothermal synthesis to grow ZnO nanorods on the surface of woven carbon fibers and implement the resulting hybridized fibers in an epoxy matrix composite. X-ray diffraction and scanning electron microscopy are carried out to study the morphology of the surface-grown nanorods and their adhesion to the substrate carbon fibers. Two-layered hybrid composite laminas are tested for their structural damping properties using dynamic mechanical analysis (DMA). It is observed that the ZnO nanorods can enhance the damping figure of merit of the composites by 40 % without a major delineation in the storage modulus. The enhanced damping performance can be attributed to the additional surfaces manifested by the presence of the ZnO nanorods and, consequently, augmenting the sliding and frictional mechanisms. Furthermore, ZnO as piezoelectric material has the energy scavenging advantages over other 1D nanostructures which ultimately constitutes the fabricated hybrid composites as a multifunctional structural material for energy harvesting applications.