Why Wood Does Not Melt?

It is taught in schools that application of heat turns solid into liquid and then to gas. While this works out in most parts, there are some exceptions that do not seem to follow the rule. For example, wood simply burns instead of melting. While it may seem obvious, there is quite a bit of science involved that not many are aware of. For better understanding, let us take a look at reasons why wood does not melt upon application of heat.

Composite material

Wood has an entirely different chemistry, as it is made up of several different materials. Wood is composed of lignin, cellulose, hemicellulose, water and extractives. All of these have different chemical properties. Wood is not an element or a simple compound like water. When heat is applied to wood, its inherent compounds start to break down in a distinct manner. As a result, wood loses its original bio-chemical form. Upon combustion, wood loses all of its original chemical properties. Instead of melting, wood is broken down into charcoal, methanol, water, carbon dioxide and various other byproducts.

Can wood melt if heated in vacuum?

Wood combusts upon application of heat via oxygen present in air. This has often lead people to ask if wood will melt if heated in a vacuum. While the idea seems good in theory, the fact is that it will still fail to melt wood. Surely heat can evaporate water and other volatile matter present in the wood, when heated in a vacuum. But due to the long cellular fibers present in wood, reaching a liquid state will not be possible. Furthermore, even in a vacuum environment, wood will start to break down into various chemicals including charcoal, methanol and methane.

So, what you will get is some liquid substances, mostly charcoal. If you use a condensation apparatus, it will be possible to collect and convert the various gases in liquid form. However, there won’t be any possibility to return it back to wooden state.

While melting wood may not be possible with current technology, things could change with newer technologies of the future. The primary bottleneck is the long cellular fibers that have high melting point and lower combustion temperature. If any of these variables can be tweaked with a new technology, it may be possible to melt wood.

It may take some time, as there does not seem to be any real need to convert wood into liquid and back. Scientific research is usually targeted at projects that could be commercially utilized. Turning wood into liquid and back doesn’t appear to have any commercial value as of now.