Under development: Lignin-based aerogels with excellent insulating properties

Aerogels are solid, highly porous materials with a low density and low thermal conductivity.
A team led by the Professor Irina Smirnova at the TU HH has now developed an aerogel that is largely lignin based – pure lignin based panels are not feasible -, using lignin derived from residual wood and wheat straw.
The lignin was extracted using two environmentally friendly treatment methods, based on Organosolv-and Aquasolv protocols.
Using five different gelling strategies, the lignin was then coverted into aerogels. One of the most successful approaches led to the development of hybrid lignin polyurethane aerogels with tunable densities of between 50 and 250 kg / m3. The mass-related content of lignin is 78 percent; insulation boards made from this type of Aerogel reach a thermal conductivity of 24 mW / m K ;which significantly exceeds the insulating properties of polystyrene or Rockwool. Lignin-based resorcinol formaldehyde aerogels with a surface area of 500 m2/ g, and a wide range of adjustable properties look promising. The procedure has been scaled up in the pilot.

At the end of the project, two spin-off companies from the TU HH will promote the market introduction of the material after the end of the project, manufacturing lignin and aerogels on a pilot scale for interested companies.
The first is BioMP (www.thebiomp.de), a company with expertise in the field of hot water hydrolysis and production of lignin; the second, Aerogelex (www.aerogelex.com) manufactures various types of organic aerogels and offers lignin PU Aero gel plates for industrial testing.

The project "material use of lignin: Nanoporous materials" was promoted by the Federal Ministry of food and Agriculture (BMEL) as the project carrier for specialist agency renewable raw materials e. V. (FNR). The final report is available on fnr.de 22018312 available at the grant number. On the project were in addition to the HH TU the Fraunhofer-Institute for chemical biotechnological processes (CBP), University of Vienna, the Bavarian Center for applied energy research and the company Dräger safety and Loick organic value substances involved.

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