Combustion kinetics of two core materials for sandwich structures

The thermal behavior of a polymeric foam (Divinycell H100) and balsa wood (ProBalsa LD7), which are extensively applied as core materials for sandwich panels, is investigated. Chars, produced from pyrolysis of thick samples at 950 K, reflect significant shrinkage of the sample and, for the polymeric foam, the complete loss of the cellular structure following softening. Thermogravimetric curves, measured in air at different heating rates, show that combustion takes place over a temperature range of 650-940 K (polymeric foam) and 475-740 K (balsa). The curves are well predicted by a four-step and a six-step reaction model, respectively, with kinetic parameters that are invariant with the heating rate.