Windows made of transparent wood could help keep buildings warm

A new transparent wood becomes cloudier (right) upon the release of stored heat.

Transparent wood could be used for windows

American Chemical Society

Transparent wood could one day replace glass in windows. A process for turning it see-through also gives it heat-retaining powers, which could help regulate the temperature of buildings.

Céline Montanari at the Wallenberg Wood Science Center and colleagues built on previous work which created transparent wood by removing a structural component called lignin from wood, allowing light to filter through.

For the next stage, the team soaked de-lignified birch wood in PEG (polyethylene glycol), a polymer is also found in theatre smoke machines and toothpaste. When encapsulated in the wood panels, this makes it harder for heat to cross – whether you’re insulating a building against the cold outside, or trying to keep out summer heat.

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The plastic is solid at room temperature, but melts at 30°C.

“When we build we try to use a lot of glass, but it has a drawback of being a bad insulator, so there are large amounts of heat loss,” says Montanari. “Wood is really amazing, 10 times better at insulating, but it does not transmit light.”

The composite wood is not quite a good insulator as natural wood, but is around 4 times better than high end double glazing.

The material can also bear heavy loads and is biodegradable, making it easier to dispose of than concrete or glass.

The modified wood is still not perfectly clear – when the PEG is solid, the material has a white haze similar to frosted glass. But Montanari is confident these early challenges can be overcome by tweaking the chemistry or using different species of wood.

The work was presented at a meeting of the American Chemical Society.

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source: newscientist.com