Manufacturing, Properties, and Application of Nanosized Superhydrophobic Spherical Silicon Dioxide Particles as a Functional Additive to Fire Extinguishing Powders

The method of manufacturing nanosized spherical superhydrophobic silica particles is reported. The efficiency of hydrophobized nanosilica (NS) as an additive to fire extinguishing powders (FEP) based on ammonium phosphates was evaluated. The effect of hydrophobization on the texture properties, size, and shape of the NS additive particles was studied. The surface of the fire extinguishing component is uniformly coated by spherical hydrophobized NS nanoparticles without a high-speed mixing procedure. NS additive provides a highly hydrophobic coating to the particles of the FEP + NS fire extinguishing powder. The apparent contact angle of the coated particles was found to be larger than 160°. The dynamic flow resistance of commercial and FEP + NS fire extinguishing powders was compared. The specific energy and aerated flow energy of the FEP + NS is relatively low, thus indicating a weak aerodynamic interaction between the particles in dynamic processes. It was established that the spraying resistance of FEP + NS is the lowest among the studied fire extinguishing powders (including commercial ones), so it is characterized by the best flowability.