Thermal degradation and fire performance of wood treated with various inorganic salts

The effects of Na₂WO₄, Na₂SnO₃, and Na₂MoO₄ on the thermal decomposition and fire performance of wood were characterized by thermogravimetric analysis, differential thermogravimetry, differential thermal analysis, and thermogravimetry–mass spectrometry analysis. The kinetics of thermal degradation were analyzed using Doyle's equation and the limiting oxygen index was shown to be enhanced by the addition of Na₂WO₄, Na₂SnO₃, and Na₂MoO₄. The addition of these chemicals caused a decrease in the decomposition temperature, a reduction in weight, and an increase in the amount of char produced. The activation energies of the samples were also decreased after treatment by these flame retardants, during both the charring stage and the calcining stage. The flame retardants were shown to be able to catalyze the dehydration reaction, resulting in the formation of more H₂O, CO₂, and char molecules, but less levoglucosan and levoglucose. Copyright © 2010 John Wiley & Sons, Ltd.