Plastic materials are used increasingly in different domains and the comprehension of the phenomena occurring when they are exposed to a thermal stress has become a huge challenge over years. Indeed, an accurately described thermal decomposition of materials can help both, determining the conditions for which ignition can occur and evaluating their participation to a fire growth and propagation. Numerous parameters influence the thermal decomposition, especially the irradiance level and the local oxygen concentration of the environment where decomposition occurs.

The present paper deals with the assessment of the thermal behaviour of an Acrylonitrile-Butadiene-Styrene material, considering both phenomena occurring in condensed and gaseous phases. The results of Controlled Atmosphere Cone Calorimeter and Fourier Transform InfraRed spectrometer are presented for different test conditions (variation of the oxygen concentration environment and the irradiance levels imposed at the material surface). This study allows the determination of different combustion regimes depending on the oxygen concentration. It also highlights the effects of both the oxygen richness and the heat flux on the parameters which allow assessing the material's thermal behaviour: ignition time, mass loss rates, heat release rate and emissions of combustible and hazardous gaseous compounds.

塑料材料在不同领域中的使用越来越多，而对塑料材料暴露于热应力下所产生的现象的理解已成为多年来的巨大挑战。确实，准确描述的材料热分解可以帮助确定点火可能发生的条件和评估其对火势增长和蔓延的参与。许多参数影响热分解，特别是辐照度和发生分解的环境的局部氧浓度。

本文考虑了在冷凝相和气相中都出现的现象，对丙烯腈-丁二烯-苯乙烯材料的热行为进行了评估。给出了针对不同测试条件（氧气浓度环境的变化和施加在材料表面的辐照度水平）的受控大气层锥形量热仪和傅里叶变换红外光谱仪的结果。这项研究允许根据氧气浓度确定不同的燃烧方式。它还强调了富氧量和热通量对参数的影响，这些参数可以评估材料的热行为：着火时间，质量损失率，放热率以及可燃气体和有害气体化合物的排放。