Reduction in smoke emitted and fire hazard presented by flexible poly (vinyl chloride) through novel synthesis of SnO2 supported by activated carbon spheres

A novel catalyst consisting of SnO₂ supported by activated carbon spheres (ACS), referred to as “ACS@SnO₂,” was demonstrated as being much more efficient than either ACS or SnO₂ alone. As such, it is capable of improving the thermal stability and flame retardancy of flexible poly (vinyl chloride) (fPVC). The resulting ACS@SnO₂ composite exhibits a higher reactivity and excellent stability due to the presence of evenly dispersed SnO₂ particles attached to the ACS, as well as the high degree of graphitization of the ACS. Smoke suppression and the synergistic flame‐retardant effect of the ACS@SnO₂ on the fPVC were thoroughly investigated by performing a cone calorimeter test and thermogravimetric analysis. The cone calorimeter test data reveal that the addition of the ACS@SnO₂ greatly improved the flame retardancy of the fPVC, with 32% and 58.4% decreases in the peak heat release rate and smoke production rate, respectively. This is attributed to the formation of a continuous and compact protective layer and the synergistic effects of the ACS and SnO₂ in promoting the ability of the fPVC to isolate heat and oxygen. Furthermore, the ACS@SnO₂/fPVC composite produced greatly increased amounts of char residue, thereby attenuating the fire hazard presented by fPVC composites.