The piece of glass was made from wood. Research work at the Forest Products Lab on using wood to create transparent windows is making great strides. (Photo: USDA Forest Service)
Forest Products Laboratory researcher Junyong Zhu, in co-collaboration with colleagues from the University of Maryland and University of Colorado, has developed a transparent wood material that may be the window of tomorrow. Researchers found that transparent wood has the potential to outperform glass currently used in construction in nearly every way.
Their findings were published in the Journal of Advanced Functional Materials in their paper, “A Clear, Strong, and Thermally Insulated Transparent Wood for Energy Efficient Windows”.
While glass is the most common material used in window construction, it comes with a costly economic and ecological price. Heat easily transfers through glass, especially single panes, and amounts to higher energy bills when it escapes during cold weather and pours in when it’s warm. Glass production in construction also comes with a heavy carbon footprint – manufacturing emissions are approximately 25,000 metric tons per year.
Now, transparent wood is emerging as one of the most promising materials of the future.
Transparent wood is created when wood from the fast-growing, low-density balsa tree is treated to a room temperature, oxidizing bath that bleaches it of nearly all visibility. The wood is then penetrated with a synthetic polymer called polyvinyl alcohol (PVA), creating a product that is virtually transparent.
The natural cellulose in its wood structure and energy-absorbing polymer filler in transparent wood means that it is far more durable and lighter than glass. It can withstand much stronger impacts than glass and, unlike glass, it bends or splinters instead of shattering.
Switching to transparent wood could prove to be cost efficient as well. It is approximately five times more thermally efficient than glass, cutting energy costs. It is made from a sustainable, renewable resource with low carbon emissions. It’s also compatible with existing industrial processing equipment, making the transition into manufacturing an easy prospect.