Chemical bridging of ammonium octamolybdate and silica for highly efficient smoke suppression of polyvinyl chloride-based composites

Smoke hazard is the most dangerous in a fire accident. Cheap inorganic materials such as silica may promote the smoke suppression property of polymer-based composites, but show low efficiency because of chemical inertia in burning scenario. In this work, ammonium octamolybdate (AOM) was chemically incorporated into hydrophobic nano silica (SiO 2 ) with a silane coupling agent as a bridge, and the resulting MSiO 2 -AOM displayed significantly improved smoke suppression compared with the mixture of SiO 2 and AOM. While applying typical polyvinyl chloride wood-plastic building composite (WPC), total smoke production (TSP) and the maximum smoke density (Ds max ) were respectively decreased by 37% and 42% at only 20 phr MSiO 2 -AOM (5.0 wt%). Herein, the essential reasons for the effect of MSiO 2 -AOM on overall performance of WPC were also discussed in detail. This work provides an effective method to upgrade the traditional SiO 2 to efficient smoke suppressant by a simple bridging effect.