Fabrication and Multifunctional Properties of High Volume Fraction Aligned Carbon Nanotube Polymeric Composites

Abstract

High volume fraction aligned carbon nanotube (CNT) nanocomposite specimens are fabricated using mechanical densification of CNT forests and capillarity-induced wetting of the forests with several thermoset polymers. Such nanocomposites approach the ideal morphology of collimated aligned fiber systems used in aerospace composites, and have long been expected to exhibit substantial engineering property improvements over existing systems. Polymers used are unmodified and include two aerospace-grade complex thermosets and a UV-curing thermoset used in microfabrication. Mechanical densification of the CNT forests prior to polymer introduction results in uniform nanocomposites. High volume fraction (to ~20%) CNT forests are effectively wet by the thermosets studied. Modulus, hardness, and electrical resistivity are characterized as a function of volume fraction for one of the epoxy systems. Multifunctional properties (modulus, hardness, and electrical conductivity) of the nanocomposites are strongly influenced by CNT volume fraction. Such specimens can be used to explore nano-scale interaction effects such as CNT- CNT contact effects on thermal and electrical conductivities.