Combining aerogels with honeycombs – a new stiff and flexible superinsulation

Abstract

Saving energy is the most important issue in the 21st century. New high qualitative thermal insulation materials are of critical importance to energy-efficient building design, transportation and aircraft industry. We propose to combine aramid honeycombs with aerogels to manufacture such new types of advanced insulation materials. Aramid honeycombs produced from aramid fibers by the expansion method possess extremely high stiffness-to-weight ratio and are heat-resisting up to 550°C. Aerogels are nanostructured highly open-porous solid materials synthesized by sol-gel process, mostly dried with supercritical carbon dioxide. They possess densities about 0.05-0.1 g/cm3, surface area in the range of 500-1000 m2/g, low thermal conductivity 0.01-0.03 W/mK and high sound absorption. Due to these excellent properties aerogels are brilliant insulation materials. The filling of honeycomb cells with aerogels can considerably reduce the thermal conductivity due to elimination of air convection and radiation effects. We investigated aramid honeycomb-cores with various cell sizes filled with two types of organic resorcinol-formaldehyde (RF) aerogel: a rubber-like flexible one [1] to ensure a certain elasticity of the composite which is important for some applications and a hard, brittle one produced according to Pekala synthesis route[2]. The resulting composite materials exhibit a combination of both component properties. On the one hand the aerogel decreases the thermal conductivity of the composite, on the other hand the honeycomb increases its stiffness. Thus we could produce a resilient, light insulating material with a good mechanical load capacity. The poster presents the fabrication route, the materials properties and discusses the results.