The quest for more sustainable products continues to fuel research and product development across the board. In particular, as we strive to produce products that are biodegradable and with a smaller carbon footprint, cellulose-based products are receiving increased attention. In past reports, we have discussed emerging products such as cross-laminated timber (CLT), wood-based textiles and wood-concrete composites, along with many other innovative applications. Here are some of the most recently reported innovations and commercialization updates.
Market Development of Cross-Laminated Timber (CLT)
CLT has become a wood residual success story. Globally, the CLT market is expected to enjoy double-digit growth in this decade, exceeding a market valuation of $2.25 billion by 2027, according to Global Market Insights Inc. Sustainability and engineering attributes are making CLT usage increasingly popular in structural construction applications. The market continues to expand as building codes are being revised to allow CLT in multistory buildings. North America accounts for about 43% of global production, with 14 plants in production as of the end of 2019, and three other new facilities under production.
Aside from environmental and engineering benefits offered by mass timber, people like to work in wood buildings. “Clients are recognizing the appeal of mass timber to attract tenants and end-users who are seeking a social and environmentally responsible workplace,” Patrick Fejér, principal at B+H Architects, recently told the Toronto Globe & Mail. Mass timber buildings, he said, “can prove to be a powerful ally in talent attraction and retention by making visible an organization’s identity and core values.”
Wood Fiber Insulation for Structures
There are 15 wood fiber production plants in Europe, serving a $700 million market. Wood fiber insulation offers a much lower carbon footprint option than other alternatives. Expansion into the North American market, however, has failed to materialize.
That situation is about to change, however. A new wood fiber insulation plant in Maine is scheduled to begin production in 2022. The TimberHP facility, an offshoot of Belfast, Maine-based GO Lab (https://golab.us/), will be located in a shuttered pulp and paper plant, using local woody residuals as feedstock.
The plant will produce three products, including insulated board, batt, and loose-fill wood fiber. According to the manufacturer, the carbon footprint of the wood insulated board is four times better than that of foam plastic boards and seven times better than mineral wool board, its main competitors. For batt, the carbon footprint is five times better than fiberglass and seven times better than mineral wool.
3D Printing Using Sawdust and Lignin
Having trouble matching an antique molding or furniture component? That’s no problem for Forust. Burlington MA-based Forust (www.forust.com) is a startup that prints wood products using sawdust derived from the wood products industry and other waste materials. The company’s process involves spreading layers of specially treated sawdust, using a biodegradable and non-toxic binder to turn them into a wood product. Various grain effects can be produced. The resulting product, called Forust, has a similar strength to solid wood. It can be readily worked, fastened, and finished using conventional wood finishing methods. The product was developed by 3D Desktop Metal, a Boston-based printing technology company.
Ronald Rael, one of the co-inventors, is a professor of architecture at the U.C. Berkeley College of Environmental Design. He recently stated that the development of Forust can address a range of wood manufacturing challenges such as producing replacement parts for historic restorations or creating luxury wood products.
Transparent Wood to Replace Glass
Forest Products Laboratory (FPL) researcher Junyong Zhu in co-collaboration with colleagues from the University of Maryland and the University of Colorado has developed a new cheap and effective process to produce transparent wood. Used as a substitute for glass, transparent wood has the potential to reduce energy requirements and greenhouse gas emissions. Regulating building temperatures accounts for 14% of primary energy consumption in the United States, and one-quarter of this energy is lost through inefficient glass windows in cold weather. Transparent wood windows, on the other hand, boast a thermal conductivity more than five times lower than glass, and toughness three times greater than glass.
To create transparent wood, a thin veneer of rotary cut wood can be treated with a solution of hydrogen peroxide, and after an hour in the sun or under a UV lamp, the peroxide bleaches out the color but leaving the lignin intact and the wood turned transparent. The process has yet to become commercialized but holds significant potential.
Bio-based Coating for Wood Outperforms Traditional Synthetic Options
This non-toxic wood coating resists abrasion, stain and sunlight, according to researchers.
Protective coatings help protect wood material from degradation caused by exposure to sunlight and moisture. Researchers at Aalto University in Finland have developed a safe, low-cost and high-performing wood coating derived from lignin, a natural polymer abundant in wood and other plant sources.
“Our new coating has great potential to protect wood,” commented researcher Alexander Henn, a doctoral candidate at Aalto University, The School of Chemical Engineering. “It’s more water repellent than a lot of commercial coatings because it retains the natural structure of wood and its micro-scaled roughness. Since it’s hydrophobic, the coating is also quite resistant to stains, while lignin’s inherent structure resists color changes from sunlight. It also does an excellent job of retaining wood’s breathability.”
In the range of 60-120 million metric tons of lignin is isolated worldwide from pulping and biorefinery processes, of which 985 is incinerated for energy recovery. The limited performance results of previous lignin-based coatings have hampered commercialization.
“Lignin as a coating material is actually very promising with its many benefits compared to the synthetic and bio-based coatings currently used,” stated Monika Österberg, head of the Department of Bioproducts and Biosystems at Aalto University. “It has excellent anti-corrosion, anti-bacterial, anti-icing, and UV-shielding properties. Our future research will concentrate on developing characteristics like elasticity of the coat.
Replacing Lithium-Ion Batteries with Cellulose Supercapacitors
Nippon Paper Industries aims to utilize cellulose nanofibers to create and commercialize supercapacitors that could store and release energy more efficiently and more sustainably than currently available options.
According to Toru Nozawa, Nippon Paper’s CEO, cellulose nanofiber (CNF) supercapacitors could be used to replace lithium batteries in applications such as cell phones and vehicles. The company intends to demonstrate a pilot energy storage system by 2025 and fully commercialize the technology in the following decade.
At present, supercapacitors have an extremely limited storage capacity compared to lithium-ion batteries. As a result, usage has been limited to niche applications. In the March 2021 issue of the journal Nature, however, scientists provided evidence that supercapacitors using CNFs could be used to store large amounts of electricity and have potential suitability for handheld electronics, transportation and for the storage of renewable energy.
Lignin-based battery research and development is also underway in Europe. Stora Enso recently opened a 10-million-euro pilot facility in Finland to manufacture a wood-based carbon, branded as Lignode, for use in batteries. The plant will produce smaller batteries for use in consumer electronics and electric vehicles (EVs). Eventually, it hopes to also manufacture large-scale energy storage systems using Lignode.
Research into new applications for wood residuals continues to be topical, and increasingly, urgent. As a bio-based material, it offers the benefits of biodegradability and a low carbon footprint. It provides the opportunity to replace materials with a much greater carbon footprint, as well as scarce materials such as lithium. It will be exciting to see which of these innovations become fully commercialized in the years ahead. Wood is increasingly being appreciated as a critical material for the future.
