Processing and compressive properties of aerogel/epoxy composites

Aerogels are ultra-lightweight materials composed of almost 99.98vol.% of porosity and present excellent opportunities for developing lightweight composite materials. Special properties such as electrical insulation and controlled dielectric constant can be generated in such composites. Ultra-low density and hydrophobic nature of aerogels make it difficult to mix them in epoxy resins. The present research is aimed at developing fabrication methods for aerogel/epoxy composites. The development of such methods requires encapsulating the aerogel particles in epoxy resin without infiltrating them. Compression tests are conducted on these composites and their deformation and fracture behavior is studied. The composites are found to have compressive failure strain of over 25%. It is observed that the higher density composites showed higher compressive modulus but lower yield strength. The reduction in the yield strength is attributed to the early crack initiation in these specimens. (c) 2007 Elsevier B.V. All rights reserved.