Measurements and Modeling of the Behavior of Charring Polymers in Fires

美国每年在火灾中造成的生命和财产损失很高，这突显了对火灾和消防安全进行更多研究的必要性。天然和合成的有机聚合物是最常见的材料，主要负责火灾的传播。第一阶段的目标是论证FG-DVC计算机模型和TG-FTIR技术的可行性，FG-DVC计算机模型包括解聚、交联以及焦炭、焦油和气体的形成过程，TG-FTIR技术将热重分析仪(TGA)与FT-IR相结合用于释放气体分析，用于测量和模拟感兴趣的火灾条件下聚合物的降解。由于炭化聚合物作为阻燃材料的重要性，第一阶段的主要重点是酚醛树脂，这是炭化聚合物的一个重要商业例子。本工作的主要结论如下：1)FG-DVC模型可以在较宽的条件下预测苯酚、甲醛和其他炭化聚合物的动力学、产物演化、焦油产率和焦油分子量分布；2)TG-FTIR方法可以提供聚合物燃烧行为的几个方面的信息：动力学、降解机理、结焦、气体毒性、气体和结焦热值、焦油形成和阻燃性能。3)为了进一步发展FG-DVC模型作为火灾模型中炭化聚合物的子模型，确定了需要一个新的实验来提供关于炭化表面的热和辐射性质的信息。这一需求可以通过将在第二阶段开发的新版本的TG-FTIR实验来满足，该实验包括FT-IR发射和透射谱。第一阶段和第二阶段联合计划的最终目标是开发一种实验室规模的方法，用于评估作为聚合物结构和火灾条件函数的相对易燃性。该产品将包括一个集成的软件和硬件包，它利用TG-FTIR分析方法以及对该方法和FG-DVC模型的修改作为关键组件。

The high loss of life and property in fires each year in the U.S. underscores the need for additional research on fires and fire safety. Natural and synthetic organic polymers are most frequently the materials which are primarily responsible for the propagation of fires. The Phase I objective was to demonstrate the feasibility of applying the FG-DVC computer model, which includes the processes of depolymerization, crosslinking, and the formation of char, tar, and gases, and the TG-FTIR technique, which integrates a thermogravimetic analyzer (TGA) with an FT-IR for evolved gas analysis, to the measurement and modeling of the degradation of polymers under conditions of interest in fires. Because of the importance of charring polymers as flame resistant materials, the primary emphasis in Phase I was on phenol formaldehyde resin, which is a commercially important example of a charring polymer. The main conclusions from this effort can be summarized as follows: 1) The FG-DVC model can be generalized to predict kinetics, product evolution, tar yields, and tar molecular weight distributions for phenol formaldehyde and other charring polymers over a wide range of conditions; 2) the TG- FTIR method can provide information on several aspects of polymer combustion behavior: kinetics, degration mechanisms, char formation, gas toxicity, gas and char heating value, tar formation, and flame retardance. 3) In order to further develop the FG-DVC model as a submodel for a charring polymers in a fire model, a need was identified for a new experiment to provide information on the thermal and radiative properties of a charring surface. This need can be met by a new version of the TG-FTIR experiment, to be developed in Phase II, which includes both FT- IR emission and transmission spectroscopy. The ultimate goal of the combined Phase I and Phase II programs is the development of a laboratory scale methodology for assessing the relative flammability as a function of polymer structure and fire conditions. The product would consist of an integrated software and hardware package which utilized the TG-FTIR analysis method and modifications of this method and the FG-DVC model as key components.