Girardin Bertrand, Fontaine Gaëlle, Duquesne Sophie, Försth Michael, Bourbigot Serge
Unité Matériaux et Transformations (UMET)-CNRS UMR 8207-Group Reaction and Resistance to Fire (R2Fire), École Nationale Supérieure de Chimie de Lille, University of Lille, Avenue Mendeleiev, CS 90108, 59652 Villeneuve d'Ascq Cedex, France.
SP Fire Research, SP Technical Research Institute of Sweden, P.O. Box 857, SE-501 15 Borås, Sweden.
Materials (Basel). 2015 Nov 20;8(11):7837-7863. doi: 10.3390/ma8115428.
The pyrolysis of solid polymeric materials is a complex process that involves both chemical and physical phenomena such as phase transitions, chemical reactions, heat transfer, and mass transport of gaseous components. For modeling purposes, it is important to characterize and to quantify the properties driving those phenomena, especially in the case of flame-retarded materials. In this study, protocols have been developed to characterize the thermal conductivity and the heat capacity of an ethylene-vinyl acetate copolymer (EVA) flame retarded with aluminum tri-hydroxide (ATH). These properties were measured for the various species identified across the decomposition of the material. Namely, the thermal conductivity was found to decrease as a function of temperature before decomposition whereas the ceramic residue obtained after the decomposition at the steady state exhibits a thermal conductivity as low as 0.2 W/m/K. The heat capacity of the material was also investigated using both isothermal modulated Differential Scanning Calorimetry (DSC) and the standard method (ASTM E1269). It was shown that the final residue exhibits a similar behavior to alumina, which is consistent with the decomposition pathway of EVA/ATH. Besides, the two experimental approaches give similar results over the whole range of temperatures. Moreover, the optical properties before decomposition and the heat capacity of the decomposition gases were also analyzed. Those properties were then used as input data for a pyrolysis model in order to predict gasification experiments. Mass losses of gasification experiments were well predicted, thus validating the characterization of the thermo-physical properties of the material.
固体聚合物材料的热解是一个复杂的过程，涉及化学和物理现象，如相变、化学反应、热传递和气态成分的质量传输。出于建模目的，表征和量化驱动这些现象的特性非常重要，尤其是对于阻燃材料而言。在本研究中，已开发出协议来表征用氢氧化铝（ATH）阻燃的乙烯-醋酸乙烯酯共聚物（EVA）的热导率和热容。针对材料分解过程中识别出的各种物质测量了这些特性。具体而言，发现热导率在分解前随温度降低，而在稳态下分解后获得的陶瓷残渣的热导率低至0.2W/m/K。还使用等温调制差示扫描量热法（DSC）和标准方法（ASTM E1269）研究了材料的热容。结果表明，最终残渣表现出与氧化铝相似的行为，这与EVA/ATH的分解途径一致。此外，两种实验方法在整个温度范围内给出了相似的结果。此外，还分析了分解前的光学特性和分解气体的热容。然后将这些特性用作热解模型的输入数据，以预测气化实验。气化实验的质量损失得到了很好的预测，从而验证了材料热物理特性的表征。
