The possibilities that wood offers never cease to amaze. It is a renewable, recyclable and sustainable material that not only has many and varied industrial applications, from making furniture to building wind towers and skyscrapers, including packaging, textiles, and clean energy, but it also helps in the challenges posed by climate change through carbon sequestration.
Researchers have come a long way since humans started to use wood to make tools, and now, thanks to applied technology, wood-based products include among others, transparent wood, which is stronger and lighter than glass, 3D prints made using upcycled waste by-products from the wood manufacturing and paper industries and more sustainable wood-based electronics.
These advances open up a whole new range of wood usage and improve production methods of supplies for different industries, making them more sustainable and cost-efficient, in a context when turning to a bio-based circular green economy is a must.
Transparent wood for construction
At the University of Maryland researchers have come out with a new method to turn wood into a transparent material. It is almost as clear as glass but stronger and with better insulating capacities.
Cellulose and lignin are the two main ingredients of wood. Its lack of transparency comes from the combination of these two components: lignin absorbs light, and the chromophores –molecules present in lignin– make wood look brown; the fibres in the wood mainly comprise cellulose and are hollow tube-like structures that spread light, further reducing wood’s transparency. The first attempts to making transparent wood focused on removing lignin, but they were chemically hazardous and time and energy consuming.
The new approach is easy and cheap. Using hydrogen peroxide, a chemical commonly used to bleach hair, the scientists modified the chromophores, so they no longer absorb light and give colour to wood.
The scientists brushed hydrogen peroxide to planks of wood one meter long and a millimetre thick; then left the planks under sun light for one hour approximately which bleached out the chromophores leaving the lignin intact but turning the wood white. The next step was infusing the wood with a tough transparent epoxy designed for marine use, which filled in the spaces and pores in the wood and then hardened them. This process made the white wood transparent.
The process can be applied to large pieces of wood, which could lead to producing transparent building materials that could replace glass, offering additional hardness and insulation properties.
Currently, the French material science company Woodoo based in Paris, is working with collaborating partners on a project called Woodoo Augmented Wood. The research is focused on integrating electronics into a touch-sensitive wood they have developed. The car industry is very interested in this development, as the material, which transmits light, can be used to make “wooden panels for ‘tactile dashboards’ in cars” as explained Timothée Boitouzet in a recent article.
3Dprinting with wood
A few days ago, the 3D printing company Desktop Metal launched Forust, a new process that upcycles cellulose dust and lignin, which are waste by-products from the wood manufacturing and paper industries, re-materializing them into end-use fibrewood-based parts through high-speed 3D printing.
This patented single pass binder jetting Additive Manufacturing technology offers architects, manufacturers, and designers a new way to produce high end custom fibrewood-based products for home décor, interiors, transportation and architectural design with a lower carbon footprint, and all in a cost and time efficient manner.
Wood based LEDs and electronics
Prof. Berglund, who heads the WoodNanoTech project, uses wood as a template for nanotechnology. The process to do this implies stripping out the lignin, introducing an optically-compatible polymer, and adding other technology to broaden its functionality. One of the most exciting applications for Berglund is embedding quantum dots in wood to create light-emitting diodes (LEDs). “The idea is that your ceiling would be a wood panel, and the wood panel would have this LED function, so you can have indoor lighting directly from the ceiling,” he explained to media.
Another interesting line of research are wood-based electronics. The Microelectronics Research Unit, University of Oulu, Finland is now approaching the use of wood to make a 6G radio device.