In an era of steel and glass, wood may seem a bit old school. But transparent wood is emerging as one of the most promising materials of the future.
Transparent wood is a glass-like material made by treating balsa tree wood in a vat of sodium chlorite. The process involves removal of a component of wood called lignin - which provides it strength and colour. A synthetic material is then penetrated into the wood which fills the pores left by the removal of lignin. The resulting product is transparent just like plastic and also has properties of plastic. It can resist impacts better than glass and can bend unlike glass that shatters into pieces.
However, the whole process makes use of a lot of chemicals and produces liquid waste which is not quite easy to recycle. Also, it can weaken the wood.
Researchers at the University of Maryland have come up with a new method that is quicker, uses fewer chemicals, and also leaves the wood stronger. This involves modifying the lignin instead of removing it completely.
Their method is based on the theory that lignin can be made transparent by removing only the parts of the molecule that give colour to it. So they brushed the surface of the wood with hydrogen peroxide and left it under UV light to simulate natural light; then cleaned it with alcohol and filled any empty pores with clear epoxy.
The final product thus obtained allows more than 90% light to pass through it and is 50% stronger than the product where lignin was completely removed. It is even lighter and stronger compared to glass and it is highly likely that it might replace glass in the coming years.