The development of transparent composites could potentially provide affordable window materials with enhanced energy efficiency. Transparent wood as a promising material has presented desirable performances in thermal and light management. In this work, the performance of transparent wood is optimized toward an energy efficient window material that possesses the following attributes: 1) high optical transmittance (≈91%), comparable to that of glass; 2) high clarity with low haze (≈15%); 3) high toughness (3.03 MJ m⁻³) that is 3 orders of magnitude higher than standard glass (0.003 MJ m⁻³); 4) low thermal conductivity (0.19 W m⁻¹ K⁻¹) that is more than 5 times lower than that of glass. Additionally, the transparent wood is a sustainable material, with low carbon emissions and scaling capabilities due to its compatibility with industry‐adopted rotary cutting methods. The scalable, high clarity, transparent wood demonstrated in current work can potentially be employed as energy efficient and sustainable windows for significant environmental and economic benefits.

- Journal of Advanced Functional Materials. Volume 30, Issue 1 January 3, 2020

Forest Products Laboratory (FPL) researcher Junyong Zhu in co-collaboration with colleagues from the University of Maryland and University of Colorado, have 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.

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 pane, 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.

Source: USDA