Z. Li, X. D. Cheng, L. Shi, S. He, L. L. Gong, C. C. Li and H. P. Zhang (2016) Flammability and oxidation kinetics of hydrophobic silica aerogels. Journal/Journal Of Hazardous Materials 320 350-358. [In English]
Web link: http://dx.doi.org/10.1016/j.jhazmat.2016.07.054
Keywords: Hydrophobic silica aerogel; Flammability; Oxidation kinetics; Fire; hazard; Thermal decomposition; AMBIENT-PRESSURE; THERMAL-CONDUCTIVITY; THERMOGRAVIMETRIC DATA; FLAME-RETARDANT; COMPOSITES; INSULATION; HEXAMETHYLDISILAZANE; SUPERINSULATION; MICROSTRUCTURE; BUILDINGS

Abstract: Silica aerogels (SAs) present great application prospects especially on thermal insulation, but their flammability is usually ignored. A combined study on the combustion behaviors and oxidation kinetics of hydrophobic silica aerogels prepared by ambient pressure drying (SA-apd) and supercritical drying (SA-sd) was performed by employing cone calorimeter and thermal analysis. The whole combustion process for SAs could be divided into three stages in which a fire propagation phenomenon was observed with the radial propagation velocity of 6.6-8.3 cm s(-1). Current investigations forcefully demonstrated that hydrophobic SAs were combustible and easy to flashover when exposed to a heat flux higher than 25 kW m(-2). Compared between the two SAs, the SA-sd owned a less fire risk with presenting a less fire hazard and a lower smoke toxicity than those of SA-apd. The oxidation kinetics by Ozawa-Flynn-Wall method revealed that SA-sd had larger apparent activation energies than those of SA-apd which conformed to the thermal stability analysis by TG-DSC. Furthermore, a two-step combustion mechanism was proposed to explain the combustion behaviors of SAs. (C) 2016 Elsevier B.V. All rights reserved.