Fire-resistant plant fiber sponge enabled by highly thermo-conductive hexagonal boron nitride ink

Renewable and biodegradable plant fiber sponges (PFS) can be used as substitutes for some petroleum-based polymers. They could make a positive contribution to the daily carbon footprint. However, the natural fire hazard of PFS could result in a severe safety concern and restrict their application. Herein, a highly thermo-conductive hexagonal boron nitride (h-BN) ink with anisotmpic thermal conductivity was developed as a fire retardant to modify the PFS (defined as PFS@h-BN) through a simple but effective dip-coating strategy. The additive h-BN nanosheets can be homogeneously deposited on plant fibers' surfaces to form a good protective barrier, improving their fire resistance at high temperatures. Compared to the PFS, a 29.0% enhancement in limiting oxygen index value, fourfold prolongation in time to ignition, 500s enhancement in time to flameout, 21.0% reduction in the peak heat release rate, 35.1% decrease in the total smoke release, and 1.47 MPa enhancement in compression strength (epsilon = 80%) of PFS@h-BN were achieved. The obtained PFS@h-BN meet the requirements of environmentally friendly, scalable production, good fire safety, and mechanical performances, indicating a promising structural material for safe and energy-efficient building application.

Automated summary

Renewable and biodegradable plant fiber sponges (PFS) can be improved by modifying them with a highly thermo-conductive hexagonal boron nitride (h-BN) ink as a fire retardant. The modified PFS@h-BN show enhanced fire resistance, reduced smoke release, and improved mechanical performance, making them a promising material for safe and energy-efficient building applications.