Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, sede di Alessandria, Viale Teresa Michel 5, 15121 Alessandria, Italy.
Carbohydr Polym. 2013 Feb 15;92(2):1327-34. doi: 10.1016/j.carbpol.2012.10.029. Epub 2012 Oct 17.
Thermal behaviour of polymers is generally assessed by relatively low heating rate, such as in thermogravimetry (typically at 10 °C/min), which leads to progressive decomposition of chemical bonds with increasing dissociation energy under thermodynamic control. However, polymer materials may be accidentally exposed to high heating rates such as in a fire, when their thermal decomposition, occurring through competing paths, becomes kinetically controlled and may lead to heating rate dependence of their degradation mechanisms and products. In the present paper, thermogravimetry at 100, 200 and 300 °C/min heating rates has been carried out on cotton, poly(ethylene terephthalate) and their blend fabrics, which decompose with partial charring. The obtained results show that the char, produced by thermal and thermo-oxidative degradation of such polymer materials, is affected by the heating rate essentially in terms of thermal stability and yield, depending on the type of polymer and the absence or presence of air oxygen.
聚合物的热行为通常采用相对较低的升温速率进行评估，例如在热重分析中（通常为 10°C/min），这会导致在热力学控制下，随着离解能的增加，化学键逐渐分解。然而，聚合物材料可能会意外地暴露在较高的升温速率下，例如在火灾中，此时它们的热分解通过竞争途径进行，变得受动力学控制，并且可能导致其降解机制和产物对升温速率的依赖性。在本文中，对部分碳化的棉花、聚对苯二甲酸乙二醇酯及其共混织物在 100、200 和 300°C/min 的升温速率下进行了热重分析。得到的结果表明，通过这种聚合物材料的热和热氧化降解产生的炭，其热稳定性和产率主要受升温速率的影响，这取决于聚合物的类型以及是否存在空气氧。
