University of Maryland (UMD) engineers have created a new nanowood material that is much stronger and has better insulating properties than Styrofoam.
Drawing more light on the new material, Tian Li, a postdoc student with associate professor Liangbing Hu’s group in the UMD department of materials science and engineering, said: “This can insulate better than most other current thermal insulators, including Styrofoam. It is extremely promising to be used as energy efficient building materials.”
Wood conducts heat along the channels that were used when the tree was alive to shuttle water and nutrients from roots to leaves.
However, heat trying to cross the wood grain is blocked. With the wood oriented in the right direction, heat could be blocked or transmitted as the designer desires, opines the researchers.
To test how much heat was insulated, the team measured the temperature on one side of the nanowood, while on the other side of the wood, they chose to shine a light in one test and applied heat in another test.
The researchers assert that the nanowood insulated better in both cases. The wood blocked at least 10 degrees more heat than styrofoam or silica aerogel, which had been awarded the Guinness World Record for ‘best insulator.’
The nanowood, which is white, also effectively reflects sunlight, according to the researchers.
They also tried to crush it and found that, in one direction, the nanowood was 30 times stronger than commercially used thermal insulation materials such as Styrofoam, aerogel or other foams made of cellulose.
Talking about its health benefits, nanowood’s tiny fibers don’t cause allergic reactions or irritate lung tissues, unlike glass or wool insulators.
The secret to the nanowood is the removal of lignin, the part that makes it brown and rigid. The team also removed some of the short fibers that tangle themselves in with the cellulose fibers that make up the scaffolding-like base structure of the wood. The aligned cellulose fibers then bond with each other and results in a high mechanical strength.
The UMD team was assisted by Lars Wågberg of the KTH Royal Institute of Technology, in Stockholm, Sweden. Wågberg, a member of the Wallenberg Wood Science Centre, helped analyze the behavior of cellulose fibers in the nanowood.
Image and content: Science Advances/University of Maryland