A fire-retardant coating for wood made from chitosan itaconate

Wood is becoming increasingly popular again due to an increased environmental awareness. However, wood generally needs protection from a number of external influences such as moisture, UV, stains, and also fire. The latter is a particular challenge for building materials because once ignited, untreated wood usually burns down completely without the need for a continuous external heat supply. We have recently developed a sustainable coating based on polymerised chitosan itaconate, which protects wood against moisture, UV, and stains. Freestanding chitosan itaconate films were now found to be non-flammable and do not melt when exposed to fire. Thermogravimetric analyses of these films underscore the importance of polymerisation to increase the thermal stability. When applied to wood surfaces, the coating delays the ignition and the spreading of flames. A single application already reduces the burning rate by one third. With multiple layers of the coating, the samples extinguish as soon as the external flame is removed.