My first knife the man made of stone. Later knives steel metal, and is still “authority” of metals in this area is unquestioned. As exceptions can be mentioned is that ceramic knives made of zirconium oxide.
However, as it turned out, having a basic knowledge of chemistry, you can make the knife even Styrofoam, which is clearly shown by the YouTube user kiwami japan.
For this he used some sophisticated technologies of condensation, air-filled of polystyrene foam material to obtain a foam.
Initially, he had prepared a puree of orange peels, which is then distilled got orange oil. After that, he dissolved the polystyrene foam and treated the resulting material with ethanol, finally removing the air bubbles. The result is a very hard and durable billet for making knife blades.
Judging by the video, the knife can cut Styrofoam, and even some time to maintain the sharpness of the blade. However, he is unlikely to compete with anyone, even the most simple kitchen metal knife. And yet the main idea of the experiment is to show how, with our understanding of chemistry and physics to solve unusual tasks.
Source — kiwami japan