Scientists at Harbin Institute of Technology in China have created a new lightweight carbon foam suitable for use in aerospace engineering. What’s more remarkable is how the foam was made: through burning bread in a vacuum.
The team’s recent publication in the journal American Chemical Society's Applied Materials & Interfaces details the process used in creating the carbon foam. According to the study, engineering lightweight and resilient carbon foam is still cost-prohibitive, but the new bread-based approach could alleviate the engineering difficulties associated with manufacturing carbon foam:
The creation of stiff yet multifunctional three-dimensional porous carbon architecture at very low cost is still challenging. In this work, lightweight and stiff carbon foam (CF) with adjustable pore structure was prepared by using flour as the basic element via a simple fermentation and carbonization process.
The carbon foam was created by burning bread in a vacuum chamber, a process known as pyrolysis. Pyrolysis removes all of the liquid and air contents in organic matter; in bread, this results in leaving nothing but the carbon chains formed in the chemical reactions we call ‘baking’.
According to the Chinese researchers, this foam is strong and lightweight enough to be used in many industrial and commercial applications, including aerospace engineering:
These results demonstrate a promising method to fabricate an economical, robust carbon material for applications in industry as well as topics regarding environmental protection and improvement of energy efficiency.
The recipe for the bread used in these laboratory experiments was carefully refined to ensure a desirable level of porosity - the amount of air in the bread. Since bread recipes are easily tweaked, the carbon foam resulting from subjecting bread to pyrolysis can be custom-tailored for specific applications.
Carbon foam has a low thermal conductivity and a natural resilience, making it useful for impact or vibration dampening applications or even as an insulator. Since all of the air and liquid is burned off in the manufacturing process, the carbon foam is able to retain its shape when submitted to pressure and heat.