Damping and mechanical behaviour of composite laminates interleaved with rubbery nanofibers

The development of composite components with superior damping capacity is welcome in fields like automotive and aerospace for improving comfort and reducing composite damages. Here, a structural composite with improved damping and unaffected overall mechanical properties is presented. Vibration hampering is achieved by interleaving electrospun Nitrile Butadiene Rubber/poly(∊-caprolactone) (NBR/PCL) blend nanofibrous mats into epoxy unidirectional Carbon Fiber Reinforced Polymer (CFRP) prepregs. Three laminate configurations were produced using rubbery nonwoven layers with different thicknesses (5, 10 and 20 μm) for evaluating the effect of grammage layer on CFRP damping and mechanical properties. A preliminary thermomechanical behaviour of modified CFRPs was evaluated via Dynamic Mechanical Analysis (DMA), while the influence of both interleaved mat grammage and testing temperature was more deeply investigated via destructive three-point bending (3PB) analyses. Flexural elastic modulus and strength of rubbery-modified CFPSs are comparable to unmodified laminate. Some lowering occurs only at relatively high temperature when present the highest mat grammage. Damping behaviour was evaluated by single cantilever beam vibration tests using the advanced Modified-Coulomb-Model (MCM). The interleaved NBR/PCL mats improved the composite damping up to +77%, without significantly affecting the laminate mechanical properties, weight, and thickness