High Temperature and Flammability Behavior of Nanocomposites and Polymer Blends

本项目的主要目的是阐明纳米复合材料和聚合物共混物在高温下的行为以及粘土聚合物纳米复合材料在阻燃中的作用模式。粘土-聚合物纳米复合材料最近被发现可以改善聚合物的阻燃性能，例如降低热释放速率。这些纳米复合材料的作用模式尚不清楚。它主要依赖于在热解和燃烧过程中形成的表面屏障，该屏障阻止熔融的可燃聚合物流体、空气和热量通过。将研究粘土在燃烧期间气化后通过粘土沉淀在表面积累的原理，或者如本建议所建议的那样，由于粘土在燃烧前和燃烧期间的高温下迁移到表面。对于聚合物-聚合物共混物和聚合物与阻燃剂添加剂的混合物，也提出了类似的现象。添加剂在样品整体中的分布变化取决于与表面的距离以及表面的距离，这将是重要的。低自由能组分在表面的积累会影响样品的化学均匀度和表面，从而影响着火行为、放热速率等易燃特性。利用广泛的表征技术了解这一现象将导致阻燃聚合物体系的新体系和方法的发展。阐明纳米复合材料和聚合物共混物在高温下的行为以及粘土聚合物纳米复合材料在阻燃中的作用模式将扩大我们对聚合物阻燃机理的认识，并为开发新的聚合物和聚合物共混物阻燃体系以及改进防火和环境友好产品奠定基础。阻燃材料在我们的社会中具有特殊而广泛的重要性。城市安全领域，特别是鉴于最近在纽约市和其他地方发生的事件，加上对火灾的额外必要保护，增加了这一需要。具有重要社会意义的科学技术对高中生和大学生具有重要的吸引力，向这些学生群体介绍纳米材料的阻燃效果的信息将继续作为推广计划的一部分，该计划包括通过高中研究计划、本科生研究活动以及针对少数族裔博士学生的特殊、行业支持的计划与少数族裔学生互动。目前，联合国际有三名非裔美国博士生，并得到持续的支持。拟议研究的进展将在国际出版物、科学会议和研讨会以及未来的专利中报告。这些信息还将通过高中和其他机构的合作、聚合物研究所通讯、拥有大型工业网络的理工大学的教育课程发布，并将以一个专门的研讨会计划为特色，讨论这一领域的进展，以及对这些成员的访问计划。

The primary objective of this project is to elucidate the behavior of nanocomposites and polymer blends at elevated temperatures and the mode of action of clay polymer nanocomposites in flame retardancy. Clay-polymer nanocomposites were recently found to improve the flame retarding characteristics of polymers, e.g., to decrease the rate of heat release. The mode of action of these nanocomposites is not clearly understood. It relies primarily on the formation, during pyrolysis and combustion, of a surface barrier that prevents the passage of molten polymer combustible fluids, air, and heat. The principles by which the accumulation of clay on the surface occurs by precipitation of the clay following gasification of the polymer during combustion or, as suggested in this proposal, due to the migration of the clay to the surface at the elevated temperatures before and during combustion will be studied. A similar phenomenon in regard to polymer-polymer blends and of mixtures of polymers with flame retardants additives is proposed. The change in the distribution of the additive in the bulk of the sample, depending on the distance from the surface as well as on the surface will be important. The accumulation of the lower free energy components on the surface should affect the chemical homogeneity and surface of the samples, influencing the ignition behavior, the rate of heat release and other flammability characteristics. Understanding of this phenomenon using a broad array of characterization techniques will lead to the development of new systems and approaches for flame retarding polymer systems. The primary objective to elucidate the behavior of nanocomposites and polymer blends at elevated temperatures and the mode of action of clay polymer nanocomposites in flame retardancy will expand our knowledge on the mechanisms operating in the flame retardancy of polymers and lay the foundation for the development of new systems for flame retarding of polymers and polymer blends and for improved fire-safe and environmentally friendly products. Flame retardant materials are of special, broad importance in our society. The area of urban security especially in light of the recent events in New York City and elsewhere, with the additional needed protection against fires has increased the need. Socially important science and technology is a significant attraction for high school and college students, and presentation of information on flame retarding effects of nanomaterials to these student populations will continue to be part of the outreach program, which includes the interaction with minority students through the high school research programs, in undergraduate research activities, and in the special, industry-supported programs for doctoral minority students. Presently, the co-PI's have three African American doctoral students with the on-going support. The progress in the proposed research will be reported in international publications, scientific meetings and symposia and in future patents. The information will also be distributed through the high school and other institutional collaborations, through the Polymer Research Institute Newsletter, the educational courses at Polytechnic University with its large industrial network and will feature a special symposium program dealing with the progress in this area as well as a visitation program to these constituents.