EFFECTS OF DIVERSE VARIABLES ON RESISTIVITY, RHEOLOGY, AND NETWORK VISUALIZATION OF ELECTRICALLY CONDUCTIVE EPOXY-CNT COMPOSITES

Abstract

The addition of high-aspect ratio nanometric conductive fillers (i.e., carbon nanotubes [CNTs]) to an epoxy matrix has been shown to improve electrical conductivity by many orders of magnitude. These nanocomposites, well-suited for electrostatic dissipation and electromagnetic interference applications, are of intense interest to the aerospace industry where epoxy resins are already widely employed. Future adoption and commercial production efforts are limited by a lack of understanding of how electrical and rheological properties of uncured mixtures relate to the finished composite, how they change throughout the epoxy curing process, or how these materials are affected by extreme operating environments. To bridge these gaps, the viscosity and electrical properties of uncured mixtures were characterized and correlated to cured values, potentially allowing for quality control at a point in the production process where remediation is possible. Rare-earth oxide nanoparticles, europium-doped yttria, were synthesized into CNT walls, enhancing the contrast of the conductive network in scanning electron microscopy and micro-computed tomography while also granting deep-UV fluorescence. Lastly, in-situ electrical measurements of an epoxy-CNT composite were conducted under simulated low-earth orbit conditions with instantaneous decreases in resistivity as large as 60% being documented.