Burnt bread carbon foam
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Pyrolysing bread in an oxygen-low or inert gas chamber or installation has been shown to create a type of refractory carbon foam with interesting properties. What makes this burnt bread carbon foam material attractive for experimental science is that it can be cheaply made at home using nothing but materials anyone can get from the local store.
This method was first reported in July 2016.
Being a carbon foam, this type of material has low thermal conductivity (0.06 W/m·K)), making it useful as an insulator. Measurements indicate a density of 0.29 g/cm3 and a compressive strength of 3.6 MPa. It also displays low electric conductivity.
The bread carbon foam can be easily made by wrapping a slice of bread in aluminium foil and pyrolizing it in a kiln. You can also use a blow torch and use argon, nitrogen or carbon dioxide as inert atmosphere, to reduce excessive charring. The resulting bread carbon foam tends to deform and twist. The use of an inert gas limits the destruction of the bread structure, allowing the formation of a tough structure.
Since is a good heat insulator and is refractory, this type of carbon foam can be used as an insulator.
Its low electric conductivity also gives it the interesting property of being able to transmit electrical current while being a heat insulator.
As the material is nothing but graphitized choarcoal, it has practically no toxicity, though in powdered form it may irritate the lungs. It also tends to stain, so wear proper attire when working with it.