INTERNATIONAL NEWS
Glass-like wood to insulate heat
By Martha Heil , University of Maryland
Engineers at the University of Maryland designed a transparent ceiling made of wood that highlights the natural woodgrain pattern .
director of the Center for Materials Innovation at the University of Maryland , College Park .
A . JAMES CLARK SCHOOL OF ENGINEERING , UNIVERSITY OF MARYLAND
Tiny nanostructures made of cells pass water and nutrients up and down the tree , but they hold importance here as vertically aligned channels in the wood , a naturally-grown structure that can be used to pass light along .
The team started with a small block of Douglas fir and used chemicals to selectively remove its lignin , the part that makes wood brown and strong . This makes the wood transparent to light . They left behind all the other cell structures in the wood , which provide a natural pattern .
Need light but want privacy ? A new type of wood that is
transparent , tough , and beautiful could be the solution . This nature-inspired building material allows light to come through ( at about 80 %) to fill the room but the material itself is naturally hazy ( 93 %), preventing others from seeing inside .
Materials engineers at the University of Maryland have transformed wood into a transparent building material that directs light for a diffused effect , is tougher and insulates better than glass , and has a natural wood-grain pattern . They published their results recently in the journal Nature Communications .
" In this patented research , we demonstrate the first esthetic wood with patterns following the density variation in natural wood . Such patterned , transparent wood can also block UV and heat , is mechanically strong , which could find many applications in buildings where sustainability and energy efficiency are desired ," says Liangbing Hu , Herbert Rabin Distinguished professor and
A . JAMES CLARK SCHOOL OF ENGINEERING , UNIVERSITY OF MARYLAND
Four natural woodgrain styles of “ aesthetic wood ,” a new transparent formulation of wood by engineers at the University of Maryland , College Park .
By removing a key component of wood , a block of wood can be made transparent , with natural abilities to block heat and direct light , researchers at the University of Maryland showed .
The remaining wood cell structures also direct light straight through the plank . The wood is cut against the grain , so that the channels that drew water and nutrients up from the roots lie along the shortest dimension . The cell structure that still remain bounces the light around just a little bit , a property called haze , but in general the light travels directly through microchannels in the wood . At no matter what angle the sun strikes , the light travels perpendicularly through the wood and consistently falls on the same diffuse area all day .
The researchers simulated a room with a ceiling made of the new ‘ esthetic woo ’, as the researchers have dubbed it , and showed that it insulates better than glass . Esthetic wood inherits characteristics from wood and epoxy , another major ingredient in the process . This also allows it to be tougher than glass . Esthetic wood proved to be two and a half times more effective at blocking heat than glass , and three and a half times as tough as untreated wood , or almost 15 times as tough if the wood is sliced with the grain . It also effectively blocks UV light , but allows visible light through .
The researchers liked the pattern made by the lighter brown early wood , so named because it is produced early in the growth phase of the wood , and darker latewood . Early wood has less lignin because it has less material altogether , with cell walls about a quarter as thick . The researchers also tried basswood and pine , which can be used physically similarly and have lighter wood grain patterns . Inventwood , a spin off company from UMD , is commercialising this type of transparent wood technology .
6 DECEMBER 2020 / JANUARY 2021 // www . timberiq . co . za