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Fabrication and Characterization of Sandwich Composites Containing Micro- and Nano-Channel Architectures
Abstract
Lightweight composite materials are desirable in the transportation and construction industries, specifically those which may utilize both low thermal conductivities and strong mechanical properties for application as structural, thermally insulating composites. A manufacturing technique has been developed which permits the introduction of micro- and nano-scale hollow channels into a polymer matrix, with demonstrated control over both the channel volume fraction and channel orientation. Systematic variation of the volume fraction and/or orientation of the microchannels has demonstrated excellent control over the final density, effective thermal conductivity, and mechanical performance of the resulting channeled material (with the tensile, flexure, compression, and impact properties having been evaluated to date). Additionally, control over the channel diameter allows for enhanced thermal insulation performance, as gas-phase conduction within the channels becomes limited as the channel diameters become comparable to (or smaller than) the molecular mean free path of the gas species contained within the channel network structure. Final channeled specimens exhibiting the effects imparted by the engineered channel architecture were also reinforced with low areal density fiber veils to improve the strength, stiffness, and impact performance without compromising the thermal insulation capabilities of the composite part. Rather than adhesively bonding facesheets to a microchannel core, the novel manufacturing methodology allows for integrative fabrication of the sandwich composites using both the traditional facesheet approach as well as an innovative multi-layered hybrid sandwich composite suitable for highly engineered design strategies. Despite the fact that these sandwich composites utilize the lightest carbon and aramid fiber veils commercially available, the reinforced channeled architectures demonstrate the robust mechanical properties, low bulk density, and excellent thermal insulation performance necessary for structural, thermally insulating composite materials for use in transportation and construction applications.
DOI
10.12783/asc35/34837
10.12783/asc35/34837