Feb 08, 2021 10:43:00

Developed transparent wood that is lighter and stronger than glass

A research team

at the University of Maryland has announced a technology that makes ordinary wooden boards as transparent as glass, yet stronger and has better insulation properties than glass. In the future, it is expected to play an active role as a building material to replace glass due to its high heat insulation performance.

Solar-assisted fabrication of large-scale, patternable transparent wood | Science Advances
https://advances.sciencemag.org/content/7/5/eabd7342

Scientists develop transparent wood that is stronger and lighter than glass | CBC Radio
https://www.cbc.ca/radio/quirks/scientists-develop-transparent-wood-that-is-stronger-and-lighter-than-glass-1.5902739

Wood is basically composed of ' cellulose ', which is the main component of plant fibers, and ' lignin ', which combines cellulose to create strength. Molecules called 'chromophores' contained in this lignin dye the wood brown and prevent light from passing through to the inside.

Attempts have long been made to make wood transparent by removing this lignin. However, removing lignin requires long hours of work under high heat and harmful chemical substances, which has the disadvantage of extremely high manufacturing costs.

Therefore, a research team at the University of Maryland applied hydrogen peroxide solution to a wooden board 1 meter long and 1 mm thick with an ordinary paint brush and left it in sunlight or an ultraviolet lamp for about 1 hour. did. Then hydrogen peroxide bleached the lignin and the wood turned white.

The research team then injected clear

epoxy resin designed for marine development into the wood, filling and curing all the small spaces and holes in the wood. Epoxy resin is filled in the wood, which makes the white wood transparent. The research team explains that the principle of this transparency is the same as when a white, opaque tissue is moistened with water, it becomes translucent and the other side can be seen through.

Wood made transparent by epoxy resin transmits about 90% of visible light, so it boasts high transparency like glass. At the same time, transparent wood has the strength and flexibility derived from wood, so it is harder to break than glass and is a lighter material than glass.

In addition, this transparent wood turned out to be very heat insulating. Clear wood is expected to help keep buildings energy efficient, as windowpanes are a major contributor to building heat loss. It can also be applied to the cover of photovoltaic power generation panels installed in harsh environments.

According to the research team, the wood that can be made transparent varies from balsa to oak , and it can be made transparent regardless of the direction in which the wood was cut. The research team also claims that the technology announced this time does not require a high thermal environment, resulting in lower manufacturing costs.

However, the technology announced this time is only for laboratory scale, it has not been scaled up to industrial scale, and it will take time to put it into practical use. Still, researchers described transparent wood as 'having great potential as a new building material,' and said, 'Theoretically, it is possible to make the entire house transparent.'