CAREER: Understanding Flammability of Charring Polymers

摘要本提案描述了一项为期五年的项目，重点是发展对炭化和膨胀聚合物体系燃烧的定量理解。这些系统代表了与聚合物易燃性相关的危险的最有前景和最环保的解决方案之一。它们的阻燃机制尚未被很好地理解，阻碍了材料开发的努力。PI建议设计一套结合高分辨率X射线断层扫描、热重分析和差示扫描量热仪的受控辐射热解实验。这种实验技术的结合有望得到关于热降解的动力学和热力学、焦炭形态演变和这类材料内部热流的准确数据。实验结果将使用同时开发的数值模式进行解释。该模型能够模拟三维、非均匀、非静态的物体中的瞬时导热、辐射和对流换热、传质以及多种化学反应，将对包括新一代可生物降解材料在内的多种聚合物体系中的焦生长动力学有一个深入的了解。这一理解有望改变阻燃材料设计领域，并使公共安全的质量得到改善。研究成果将在科学家和执业工程师中迅速传播，并用于加强PI与行业和专业组织建立的一系列伙伴关系。这些成果也将成为皮？S教育计划的基础。PI将为中学生开发一个互动的材料可燃性演示。这一示范将被用来培养学生S在促进消防安全的同时对科学的兴趣。PI将通过让少数族裔大学生参与消防安全研究来解决他们毕业率低的问题。PI还将开发第一个此类材料易燃性的研究生课程。

Abstract This proposal describes a five-year project focused on developing a quantitative understanding of burning for charring and intumescing polymeric systems. These systems represent one of the most promising and environmentally benign solutions to the hazards associated with polymer flammability. The mechanism of their flame resistance has not been well understood, hampering material development efforts. The PI proposes to design a set of controlled radiative pyrolysis experiments combined with a high-resolution X-ray tomography, thermogravimetric analysis and differential scanning calorimetry. This combination of experimental techniques is expected to yield accurate data on the kinetics and thermodynamics of the thermal degradation, char morphology evolution, and heat flow inside this class of materials. The experimental results will be interpreted using a numerical model concurrently developed. This model is capable of simulating transient conductive, radiative and convective heat transfer, mass transport, and multiple chemical reactions in a three-dimensional, non-homogeneous object of non-static dimensions.This project will produce an in-depth understanding of char growth dynamics in a wide range of polymeric systems including a new generation of biodegradable materials. This understanding is expected to transform the field of flame resistant material design and enable qualitative improvements in public safety. The research results will be rapidly disseminated among scientists and practicing engineers and utilized to strengthen an array of partnerships that the PI has established with industry and professional organizations. These results will also form a foundation of the PI?s educational initiatives. The PI will develop an interactive material flammability demonstration for secondary school students. This demonstration will be used to foster the student?s interest in science while promoting fire safety. The PI will combat a low graduation rate among racial minority college undergraduates by engaging them in the fire safety research. The PI will also develop the first of its kind graduate course on material flammability.