By Josh Perry, Editor
Researchers at Washington State University (Pullman, Wash.) developed an environmentally-friendly alternative to Styrofoam (polystyrene foam) from nanocrystals of cellulose and a simple manufacturing process for the new insulation that avoids the harmful solvents required to make Styrofoam.
An environmentally-friendly, plant-based material that for the first time works better than Styrofoam for insulation. (Washington State)
According to a report from the university, Styrofoam is created from harmful products, including petroleum byproducts, but previous attempts at creating alternatives were not strong enough or broke down too easily.
Washington State scientists created cellulose nanocrystals from wood pulp through acid hydrolysis. The insulating foam contains 75 percent nanocrystals along with polyvinyl alcohol, a polymer that bonds with the nanocrystals and makes the foam elastic.
“The material that they created contains a uniform cellular structure that means it is a good insulator,” the article explained. “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.”
Researchers are working on new forms of the material that would be even stronger and durable for practical applications, as well as new feedstocks that would be commercially viable.
The research was recently published in Carbohydrate Polymers. The abstract read:
“Environmentally friendly, sustainable, and high-performance thermal insulators are in high demand. Petroleum-based insulator foams usually have high thermal conductivity and pose health hazards.
“Here, we report ultralight composite foams that are highly strong, elastic, and super-insulating. The foams are composed of nanocrystalline cellulose (NCC) (74 wt%), polyvinyl alcohol (7.5 wt%), and a crosslinking agent (18.5 wt%). The fabrication process is simple and uses only water. The composite foams exhibit an elastic strain of ˜13% at a modulus of 250 K Pa and a stress of 73 K Pa at 50% strain (100+ and 18 times, respectively, higher than those of pure NCC foam); both exceed the values of reported nanocellulose-based foams with no reinforcement.
“The foams exhibit a thermal conductivity of 0.027 Wm−1 K−1, which is superior to those of traditional insulating materials. The structural integrity is also preserved after burning. Our results show that NCC-based materials can be engineered towards high-performance insulation applications.”