The newly-developed material offers as good or even better thermal performance than plastic-based insulation materials, according to researchers reporting in ACS Applied Materials & Interfaces.
Yuanyuan Li, an assistant professor at Wallenberg Wood Science Centre, KTH Royal Institute of Technology in Stockholm, said that the new insulating material is an aerogel integrated wood which is made without adding additional elements.
Researchers have been developing advanced types of aerogels and other composites for a number of years in the Wallenberg Wood Science Centre at KTH, but Li said the new method represents a breakthrough in controlled creation of insulating nanostructures in the pores of wood.
“Biobased strong aerogels could be used to replace current fossil-based aerogels for super thermal insulation, contributing to energy efficiency, bioeconomy, and sustainable society development,” Li said in a statement.
According to KTH, the process starts with delignifying wood, which leaves behind empty pores or lumen. Reducing thermal conductivity in the material is done by getting inside these large empty pores and generating thousands more nano pores inside them.
These nanoporous structures are created by partial dissolution of the cell walls followed by controlled precipitation, Li said. An ionic liquid mixture is added to partially dissolve the cell wall before water is added, which generates nanofibril networks that render the lumen nanoporous.
Li said the researchers developed a high level of control over the precipitation process, so they can create the precise level of nanoporosity to achieve ideal thermal conductivity.
Beyond building materials, Li believes the unique structure enables advanced materials for energy storage and conversion, and potentially tissue engineering.
“In packaging, for example, plastic foam such as polystyrene helps prevent heat transfer between objects and the surrounding environment, so it can keep goods cool during the shipment,” she said. “But in situ formation of nanofibril networks inside wood’s empty spaces can result in wood being highly thermal insulating.”