NPG-Iso UPE based BMC formulations were compounded with Alumina Trihydrate (ATH) from 150 to 400 phr. Deca-bromo diphenyl ether (DBDE) was compounded with and without ATH. Analysis of mass loss rate, smoke production, and heat release rate plots gives a detailed sequence of events that is consistent with their FR mechanisms. Initially endothermic decomposition of ATH occurs and controls the rate of pyrolysis in the solid state. Smoke production begins shortly thereafter but is limited to smoldering. Eventually ATH depletion in surface and near surface results in ignition. A rapid rise in HRR culminates in the first HRR peak. HRR decreases and a valley is quickly reached as ATH decomposition renews. The valley is indicative of a period of equilibrium where heat feedback from the combustion phase is balanced by fuel input from the solid phase, i.e., ATH decomposition is controlling the pyrolysis rate. The second and highest HRR peak is reached and corresponds to the complete depletion of ATH. Combustion of the remaining organics creates the peak HRR. The addition of DBDE was found to reduce the rate of heat release. The reduced HRR in turn reduces feedback of heat into the composite. This has the beneficial effect of reducing the rate of ATH decomposition. Further flattening (reduced intensity) and elongation (longer time) of the MLR, RoSP and HRR curves is observed which is indicative of improving flame retardant (FR) properties.
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