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.
