U.S. Researchers at Washington State University have developed an environmentally-friendly plant-based material that, for the first time, works better than polystyrene foam for insulation.
The foam is mainly made of cellulose nanocrystals, the most abundant plant material on earth. The researchers also developed a simple and environmentally friendly 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 School of Chemical and Genetic Engineering of Linda and Linda, is published in the journal Carbohydrate Polymers.
Researchers have been working to develop an environmentally friendly replacement for polystyrene foam or Styrofoam. Popular material, made from petroleum, is used in everything from coffee cups to materials for construction, transportation and packaging industries. But, it is made of toxic ingredients, depends on oil, does not naturally degrade and creates pollution when it burns.
While other researchers have created other cellulose-based foams, the herbal versions have not worked as well as polystyrene foam. They are not as strong, they do not isolate themselves, and they degrade at higher temperatures and humidity. To make cellulose nanocrystals, researchers use acid hydrolysis, in which acid is used to break chemical bonds.
In their work, the WSU team created a material that is made of approximately 75 percent cellulose nanocrystals from wood pulp. They added polyvinyl alcohol, another polymer that binds to the nanocellulose crystals and makes the resulting foams more elastic. The material they created contains a uniform cellular structure that means it is a good insulator. For the first time, researchers report, the plant-based material exceeded the insulation capabilities of polystyrene foam. It is also very light and can support up to 200 times its weight without changing shape. It degrades well, and burning it does not 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 capacity 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 use of petroleum-based materials and the 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 being able to transfer these properties on a large scale for the first time through this engineering approach is very exciting."
Researchers are now developing formulations for stronger and longer-lasting materials for practical applications. They are interested in incorporating low-cost raw materials to make a commercially viable product and consider how to move from the laboratory to a real-world manufacturing scale.
The work was supported by the United States Department of Agriculture and the WSU Marketing Office.
Source: Washington State University.