Abstract: From the perspective of improving the formulation of foam extinguishing agents, this study investigated the effects of gel addition method and reaction-to-gel method on enhancing the thermal protection performance of foam. The influence of gel additive, as well as the amount of gelling agent and cross-linking agent, on the thermal protection performance of foam was also studied. The experimental results showed that under a heat radiation intensity of 15 kW/m2, the addition of 1.4% xanthan gum using the gel addition method could increase the thermal protection time of conventional aqueous film-forming foam from 248 s to 335 s, achieve an improvement of 35.1%. However, the gel foam obtained using the reaction-to-gel method exhibited superior thermal protection performance. When the amount of guar gum was 1.0% and the amount of cross-linking agent was 1.0%, the thermal protection time could be significantly increased to 888.5 s, achieve an improvement of 258.3%. It was found that after the water evaporated, the gel foam formed an expanded solid film, which continued to exert a certain thermal protection effect. The reaction-to-gel method not only improved the stability of the foam liquid film but also enhanced the protective ability of the foam after its own water evaporated, significantly extending the thermal protection time of the foam.

Key words: foam extinguishing agents, thermal protection performance, gel addition method, reaction-to-gel method