Ferroconcrete-inspired design of a robust and efficient flame-retardant cellulose composite for fire prevention

The development of efficient flame-retardant cellulose-based materials has garnered significant research interest. Inspired by reinforced concrete, a robust and efficient flame-retardant modified cellulose-based composite for fire prevention was developed. The material consists of oriented cellulose fibers in bamboo as the ‘reinforcing steel’ and impregnated ammonium polyphosphate (APP) and polyethyleneimine (PEI) containing epichlorohydrin (ECH) as the ‘concrete’, which are tightly bonded together by multiple interactions under hot-pressing. Compared to the baseline PBA material, the PBA-P₃N composite exhibited a 112.8 % increase in tensile stress, reaching 247.1 MPa, and a 77.7 % increase in strain, achieving 13.2 %. The limiting oxygen index (LOI) of the composite reached 46.9 %. The peak heat release rate (pHRR) and total heat release (THR) values of the composite were 97.0 kW/m² and 8.8 MJ/m² respectively, which were reduced by 64.0 % and 45.9 %. The functional composite could still show self-extinguishing properties after being kept in the flame for 40 s. Under flame attack, the flame-retardant composite was capable of protecting underlying flammable materials for up to 15 s. The developed flame-retardant material exhibits excellent fire resistance and holds promise for application in specialized environments to enhance the fire safety of flammable products.