Citation

Li Z, Cheng X, Shi L, He S, Gong L, Li C, Zhang H. J. Hazard. Mater. 2016; 320: 350-358.

Affiliation

State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China. Electronic address: zhanghp@ustc.edu.cn.

Copyright

(Copyright © 2016, Elsevier Publishing)

DOI

10.1016/j.jhazmat.2016.07.054

PMID

27566928

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 6.6-8.3cms(-1). Current investigations forcefully demonstrated that hydrophobic SAs were combustible and easy to flashover when exposed to a heat flux higher than 25kWm(-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.

Copyright © 2016 Elsevier B.V. All rights reserved.

Language: en