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New material could replace plastic or glass in construction of energy-efficient homes
Nicola Davis
In an era of glass and steel construction, wood may seem old-school. But now researchers say they have given wood a makeover to produce a material that is not only sturdy, but also transparent and able to store and release heat. The researchers say the material could be used in the construction of energy-efficient homes, and that they hope to develop a biodegradable version soon to increase its eco-friendly credentials as an alternative to plastic, glass or even cement.
“We prepared a material that is multifunctional since it can transmit light very well and also it can store heat. We combined these two functions in a single material,” said Céline Montanari of the KTH Royal Institute of Technology in Stockholm. Montanari is presenting the work at the spring national meeting of the American Chemical Society in Orlando.
To produce the material, the team built on previous work in which they took balsa wood and removed its lignin – a component of wood that gives it strength and colour. Acrylic, which is non-biodegradable and water-repellent, was introduced into the remaining tissues where it filled both the tiny pores left by the removal of lignin and the hollow vessels that carried water in the tree. That, said Montanari, not only helped maintain the wood’s structure but also restored its strength and improved its optical properties. The upshot was a frosted-looking wood-based material.
In the latest work, the acrylic was mixed with another substance called polyethylene glycol, which permeates wood well. Crucially, polyethylene glycol also has another feature: when it is heated it absorbs energy and melts, but when temperatures fall it hardens, releasing energy in the process. The team say this property means their wood-based material, which goes from semi-transparent to transparent when warmed, could be used to make buildings more energy-efficient, with energy captured from the sun during the day released later into the interior.
However, Montanari said there was plenty of work still to do – including replacing the acrylic with a biodegradable alternative for some applications, scaling up production of the material, and carrying out computer models of buildings to see how transparent wood compares with glass.
(www.theguardian.com/environment/2019/apr/03/scientists-inventtransparent-wood-in-search-for-eco-friendly-building-material. Adaptado)
De acordo com o quarto parágrafo, o uso de polietileno glicol no material fez com que se tornasse
