The aim of the ICECLAY (Highly efficient production of ultra-lightweight clay-aerogel materials and their integrated composites for building insulation) project was to develop a new generation of low cost yet highly efficient insulation materials for building construction. Their production will also enhance the competitiveness of small and medium-sized enterprises in the EU building construction sector. While common aerogels are generally expensive and based on a hazardous production process ICECLAY developed a porous lightweight composite solution based on an environmentally friendly freeze drying process. This versatile process used only harmless and inexpensive raw materials, such as naturally occurring nanoclay minerals, water and eco-friendly low cost polymers. Project partners selected four clays with the desired properties for the ICECLAY aerogel. Natural hectorite and synthetic hectorite were found to provide the best clays for producing highly thixotropic water-gel suspensions, which become less viscous when stress is applied. Hectorite clays produced stronger gels than the other clays and interacted better with polymers to form stronger structures. The aerogel was produced in the form of boards, slim strips, granules and powder. By optimizing the freezing conditions by lowering the temperature down to -65ºC, as part of a pre-cooling stage inside the freeze-dryer chamber, aerogels developed better properties. These involved improved structural integrity and surface roughness as well as reduced average pore size as a result of smaller ice crystals being generated. Researchers developed software tools for creating performance simulation numerical models and user manuals for the thermal behaviour/conductivity of clay aerogels. A series of studies were also conducted using the models to determine the effect of microstructures of different ICECLAY aerogels on their thermal behaviour. In addition, the developed models can guide the experimental designs for desired performance if the aerogel is used for certain building components. ICECLAY has developed a highly competitive aerogel material specifically targeted at the retrofit market, where low-cost and living space area savings are as important as the need for excellent insulation.
Building insulation, aerogel, nanoclay, hectorite, polymers, thermal behaviour