The team of Academician Yu Shuhong of the University of Science and Technology of China used natural biomass and natural minerals as raw materials to prepare a pure natural imitation wood aerogel with excellent heat insulation and fire resistance. The results were published in German Applied Chemistry. The co-first authors of the paper are doctoral students Han Zimeng and Sun Wenbin, and the corresponding authors are Associate Professor Guan Qingfang and Academician Yu Shuhong of Hefei National Research Center for Microscale Physical Sciences.
As a versatile material and abundant resource, wood has been widely used for thousands of years with properties such as low density, low thermal conductivity, good mechanical properties and sustainability. In recent years, based on the understanding of wood structure, various wood-like materials with unique physical properties and wide application have also been developed, among which aerogels with excellent thermal insulation performance are one of the most important research topics. Wood-like aerogels based on plastics and resins are severely limited by poor biodegradability, which leads to the accumulation of waste and poses serious environmental problems. Wood-like aerogels based on existing nanostructure primitives are limited by their lack of sustainability and high cost. Therefore, in order to solve the current problem of unsustainability of materials, the development of low-cost, low-energy, environmentally friendly new building blocks will play a crucial role in the development of imitation wood aerogels.
Preparation and structure of all-natural gas gel Photo courtesy of China University of Science and Technology
Through an ingenious surface chemical control method, the researchers succeeded in activating the surface of micron-scale wood pellets under mild conditions, thereby exposing cellulose nanofibers. The nanofibers on the surface of these particles significantly enhance the interaction between the particles, and the combination of unidirectional freezing technology successfully constructs a strong and durable wood-like aerogel. This aerogel has a similar orientation channel structure to natural wood, and this wood-like structure can greatly reduce the thermal conductivity of aerogels, giving it an ultra-low radial thermal conductivity of 17.4 milliwatts per meter of kelvin, which is superior to existing cellulose-based aerogel materials and various commercial sponges. At the same time, the addition of natural clay nanosheets has greatly improved the fire resistance of this aerogel, which can withstand flames at a high temperature of 1300 °C and not be burned through for at least 20 minutes.
The researchers believe that the insulation and fire performance of this all-natural imitation wood aerogel are superior to natural basa wood and most commercial sponges, and are expected to become an ideal alternative to existing commercial thermal insulation materials. In addition, its natural source of raw materials and low-energy, low-emission preparation process make this aerogel biodegradable and sustainable, which can reduce the negative environmental impact of thermal insulation materials during production, use and disposal. (Source: Wang Min, China Science News)
Related paper information:https://doi.org/10.1002/anie.202211099