Mechanism of non-charring polymer thermal degradation involving two types of heat flux absorption modes

Thermal degradation of two types of non-charring polymers, high impact polystyrene (HIPS) and Acrylonitrile Butadiene Styrene copolymer (ABS), exposed to an external incident heat flux was numerically investigated based on a previously established one dimensional model. The effects of surface and in-depth absorption on the pyrolysis process of HIPS and ABS were extensively employed in literatures. The corresponding cone calorimetry tests in nitrogen atmosphere of these two polymers were simulated. The experimental and numerical results were compared to validate the developed model, including mass loss rate, temperature distribution in condensed phase, top and bottom surface temperature. Results indicate that the influences of absorption mode of incident heat flux on thermal degradation process of HIPS and ABS are similar to the conclusion of PMMA, which implies that the proposed model can be utilized in predicting the pyrolysis of non-charring polymers in inertial atmosphere with constant external incident heat flux.