Fabrication and Multifunctional Characterization of Hybrid Woven Composites Reinforced by Aligned Carbon Nanotubes

Hybrid composite architectures employing traditional advanced composites and aligned carbon nanotubes (CNTs) offer significant multifunctional performance benefits in addition to enhanced structural properties. This broadens potential applications of these hybrid composites, e.g., with improved electrical conductivity, the composites may have application in lightning-strike protection. Our previous work has explored fabrication of such composites, including aligned CNT growth on filaments/tows/weaves, wetting with a polymeric matrix, and mechanical testing of the hybrid composites. Along with fabrication advances, this paper focuses on multifunctional properties of a composite consisting of woven alumina ceramic filaments, CNTs, and a thermoset matrix. Properties explored include throughthickness and in-plane electrical conductivities, and damping of baseline and CNT-enhanced hybrid composites. Excellent wetting and low void fractions are demonstrated by optical and scanning electron microscopy inspection of laminate cross-sections. Electrical resistivities decrease significantly (x10 -6 -10 -8 ) with increasing CNT volume fraction. Damping ratio is not significantly affected by CNT volume fraction, suggesting strong bonding between the (unfunctionalized) CNTs and the matrix. Further improvements in manufacturing of the hybrid composite specimens, and investigations of other multifunctional properties (e.g., thermal conductivity and thermal expansion) will be pursued as future work.