One-Stage Synthesis of Superhydrophobic SiO₂ Particles for Struvite-Based Dry Powder Coating of Extinguishing Agent

Methods for the one-stage superhydrophobic silica synthesis with high textural characteristics and a contact angle of up to 163° as a promising functional additive for struvite-based fire extinguishing powder compositions with complex gas-generating effects have been presented. In this work the sequence of components' introduction into the reaction medium and the water amount influence during the one-stage synthesis of hydrophobic silicon dioxide on its textural, structural, morphological features and water-repellent properties were investigated. Rheological studies and assessment of the hydrophobic properties of fire extinguishing compositions, obtained with the synthesized silicon dioxide particles, allowed determining the optimal characteristics of a functional additive for compositions with struvite. The developed functional additive made it possible to implement the use of crystalline hydrates (struvite) in a fire extinguishing composition. Its inhibitory effect on flames is no less than two times greater than for widely used ammonium phosphates.