By Tina Hilding, Voiland College of Engineering and Architecture

RICHLAND, Wash. – Washington State University researchers have developed an environmentally-friendly, plant-based material that for the first time works better than Styrofoam for insulation.

The foam is mostly made from nanocrystals of cellulose, the most abundant plant material on earth. The researchers also developed an environmentally friendly and simple manufacturing process to make the foam, using water as a solvent instead of other harmful solvents.

The work, led by Amir Ameli, assistant professor in the School of Mechanical and Materials Engineering, and Xiao Zhang, associate professor in the Gene and Linda School of Chemical Engineering and Bioengineering, is published in the journal .

Researchers have been working to develop an environmentally friendly replacement for polystyrene foam, or Styrofoam. The popular material, made from petroleum, is used in everything from coffee cups to materials for building and construction, transportation, and packaging industries. But, it is made from toxic ingredients, depends on petroleum, doesn’t degrade naturally, and creates pollution when it burns.

While other researchers have created other cellulose-based foams, the plant-based versions haven’t performed as well as Styrofoam. They are not as strong, don’t insulate as well, and degraded at higher temperatures and in humidity. To make cellulose nanocrystals, researchers use acid hydrolysis, in which acid is used to cleave chemical bonds.

In their work, the WSU team created a material that is made of about 75 percent cellulose nanocrystals from wood pulp.  They added polyvinyl alcohol, another polymer that bonds with the nanocellulose crystals and makes the resultant foams more elastic. The material that they created contains a uniform cellular structure that means it is a good insulator. For the first time, the researchers report, the plant-based material surpassed the insulation capabilities of Styrofoam. It is also very lightweight and can support up to 200 times its weight without changing shape.  It degrades well, and burning it doesn’t produce polluting ash.

“We have used an easy method to make high-performance, composite foams based on nanocrystalline cellulose with an excellent combination of thermal insulation capability and mechanical properties,” Ameli said. “Our results demonstrate the potential of renewable materials, such as nanocellulose, for high-performance thermal insulation materials that can contribute to energy savings, less usage of petroleum-based materials, and reduction of adverse environmental impacts.”

“This is a fundamental demonstration of the potential of nanocrystalline cellulose as an important industrial material,” Zhang said. “This promising material has many desirable properties, and to be able to transfer these properties to a bulk scale for the first time through this engineered approach is very exciting.”

The researchers are now developing formulations for stronger and more durable materials for practical applications.  They are interested in incorporating low-cost feedstocks to make a commercially viable product and considering how to move from laboratory to a real-world manufacturing scale.

The work was supported by the US Department of Agriculture and WSU’s Office of Commercialization.

By Maegan Murray, ���سԹ�

RICHLAND, Wash. – Groundbreaking nanotechnology designed to protect cherries, apples and other popular fruits from frost damage is showing positive results in tests by Washington State University researchers.

The research team recently received a $500,000 grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture to develop plant-based nanocrystals that coat and protect fruit buds during cold spells in the spring, when temperatures rise and fall unpredictably. The team also received an additional $100,000 from the tree fruit growers of Washington state through the Washington Tree Fruit Research Commission to partially fund field trails in support of the technology.

The unique nanocrystal solution was formulated by Xiao Zhang, associate professor at ���سԹ�’ Bioproducts, Sciences and Engineering Laboratory, and a team of collaborators representing multiple disciplines.

“Frost damage happens in spring, as the flowers open and the sensitive tissues in the plant are exposed,” said Matthew Whiting, scientist and professor of horticulture at WSU’s Irrigated Agriculture Research and Extension Center. “If we get a warm week, it signals to the plant that it needs to wake up.

“But plants lose their tolerance to the cold quite quickly, and that’s when we see frost damage,” Whiting added. “You see a lot of crop damage as a result.”

Positive results with preliminary trials

The team, led by professor Qin Zhang, director of WSU’s Center for Precision and Automated Agricultural Systems, also includes Xiao Zhang, Matthew Whiting, and Changki Mo, ���سԹ� associate professor of mechanical engineering. Together they conducted their first field trial with the nanocrystals this spring. It showed positive results.

The team will continue the trials over the next three years, seeking to perfect the dosage and application strategy, in addition to the nanocrystal technology.

“We will explore thermal properties of the nanocrystal spray, and focus on fully understanding the mechanism of nanocrystals in frost damage reduction,” Mo said.

If it proves feasible, the technology could have a large impact on the agriculture industry.

“Our preliminary results show the technology to be very promising, even better than we were expecting,” Qin Zhang said. “If we prove that the technology works, and if the method of application is perfected, it will not only have applications in tree fruit, but in many other crops, and beyond. The potential for this technology is huge.”

Unique and renewable characteristics

Since the nanocrystals are made from plant-based material, they represent a more environmentally friendly method for controlling temperatures for crops than current techniques.

Currently, growers use methods such as wind turbines to circulate air and raise the temperature of cold pockets in orchards. Or, they use heaters that cost upwards of thousands of dollars per night, which also give off significant pollution.

“With these unique structural characteristics and physical properties, and the fact that the nanocrystals are all made out of biobased materials and are considered renewable, we are identifying a high-value niche application for tree fruit and frost prevention and protection,” Xiao Zhang said.

Cross disciplines for the future of fruit protection

Researchers from across several disciplines at WSU are working to perfect the nanocrystal method, ensuring a quality product built for industry use, Qin Zhang said.

“No single person who works in chemical engineering and nanocrystal technology, horticulture, mechanical engineering or precision agriculture has complete knowledge on the subject,” Qin Zhang said. “It is truly a transdisciplinary team. Everyone provides expertise in their particular field. This integrated team is covering all knowledge to conduct this research.”

 

Contacts:

• Qin Zhang, director and professor at WSU’s Center for Precision and Automated Agricultural Systems, 509-786-9360, qinzhang@wsu.edu
• Xiao Zhang, associate professor at Voiland School of Chemical Engineering and Bioengineering, 509-372-7647, x.zhang@wsu.edu
• Changki Mo, ���سԹ� associate professor of mechanical engineering, 509-372-7296, changki.mo@wsu.edu
• Matt Whiting, scientist and professor of horticulture at WSU’s Irrigated Agriculture Research and Extension Center, 509-786-9260, mdwhiting@wsu.edu
• Maegan Murray, ���سԹ� public relations specialist, 509-372-7333, maegan_murray@wsu.edu