Abstract

Aerogels are organic or inorganic materials that are unique in many ways. As the name suggests aerogels have a porous structure and contain a high percentage of air (>95%). This results in useful properties like low density, a high specific surface area and low thermal conductivity (~0.013W/m∙K). The resulting superior thermal insulation properties are not achieved with common insulation materials like expanded polystyrene 0.035W/m∙K at 10 °C. The problem with Aerogels as a bulk material is their stiffness which results in damage to the porous system under mechanical stress. This brittleness should be overcome using aerogel fibers instead. In fiber morphology, silica aerogels become more flexible and could be used as an ultralight thermal insulator for example. In the project “EvA”, aerogel filament nonwovens made of Polyacrylonitrile (PAN) were developed at ITA. In addition, fibers and textile structures of silica aerogels could be realized and tested for the first time in the VIP+ project “Silica Aero”. PAN aerogel textiles can preferably be used in price-sensitive standard insulation applications with a large market volume. The silica aerogel textiles are meant for application areas with special requirements regarding chemical and thermal resistance. In these fields more expensive products are used. The low weight of the nonwovens and the developed process are linked with cost savings and advantages in materials handling for both aerogel types in comparison to the established competitor products.

Keywords: Aerogel; Polyacrylonitrile; Silica; Fiber; Nonwoven; Insulation; Lightweight; Wetlaid; Solution spinning

Abbreviations: EPS: Expanded Polystyrene; PAN: Polyacrylonitrile; ITA: Institut für Textiltechnik der RWTH Aachen University; BMWI: Federal Ministry for Economic Affairs and Energy (Germany) FKZ: Funding Code