Insulation – types, features, and flaws
Researchers have developed an environmentally friendly plant-based material that outperforms traditional foam in thermal and mechanical performance. It retains its properties under the influence of water and high temperature.
Expanded polystyrene (traditional styrofoam) is used in a variety of applications, from materials for construction and transportation to coffee cups and packaging. However, it depends on oil, contains toxic substances and pollutes the environment..
Working to create an effective alternative, a team at Washington State University developed a material that is 74% cellulose nanocrystals from wood pulp. Another 7.5% is accounted for by polyvinyl alcohol, which binds to nanocellulose crystals and increases the elasticity of the structure. The remaining 18.5% is occupied by the crosslinking agent.
The resulting composite foam has a homogeneous cellular structure, making it a good insulator. Its thermal conductivity is 0.027 W / (m ∙ K), which is superior to that of traditional expanded polystyrene. The new material is also very lightweight and can withstand the weight 200 times its own, without changing the shape. It decomposes well and does not form polluting ash when burned.
The team also developed a simple manufacturing process using water as a solvent and obtained cellulose nanocrystals by acid hydrolysis..
Next, scientists will work on increasing the strength and durability of the material, developing new compositions. They also plan to use inexpensive raw materials so that eco-friendly foam can be produced commercially..
Recall that earlier researchers have made thin polymer films that conduct heat better than many metals and ceramics..
text: Ilya Bauer, photo: Washington State University