Damping Characteristics of Epoxy-Reinforced Composite with Multiwall Carbon Nanotubes

In the current work, the damping characteristics of epoxy-reinforced composite with multiwall carbon nanotubes (MWNTs) have been investigated. The effect of reinforcement weight percentage and the influence of carbon nanotube (CNT) sizes on the damping are examined. The frequency dependent damping behavior of nanocomposites has been evaluated. A nearly 85% increase in loss modulus is observed for nanocomposites reinforced with CNTs of high specific surface area (SSA) against 53% with CNTs of lower aspect ratio and SSA at 0.75% filler percentage. Hence, it is evident that CNTs with a high aspect ratio and SSA are very effective in improving the damping behavior of polymer composites. An increase in storage modulus of about 10% is noticed at 0.5% CNT filler percentage followed by a marginal reduction at 0.75%, which clearly indicates that the percentage of reinforcement plays a major role in enhancing the stiffness properties. Interestingly, the CNT nanocomposites have been found to exhibit better damping characteristics at higher frequencies. An interfacial stick-slip mechanism between an epoxy matrix and CNTs is accounted for enhancement of damping in nanocomposites.