(337bk) Efficient and Sustainable Manufacture of Polymeric Composites and Their Applications in Fire Safety

Polymeric materials provide numerous advantages to society in everyday life, such as buildings, housing, vehicles, aircraft, and commercial products. One significant drawback is the high flammability of many synthetic polymers due to their energy-dense hydrocarbon-based chemical structures. The use of Intumescent Flame Retardants (IFRs) is considered an environmentally friendly and cost-effective strategy to suppress potential fire hazards from synthetic polymers. However, some conventional IFRs are neither efficient in developing a thermally stable protective layer nor reducing the release of toxic byproducts during polymer combustion. Metal-organic frameworks (MOFs) are newly developed porous materials and their unique inorganic-organic hybrid nature exhibits greater compatibilities with polymer matrix and unique synergistic catalytic effects. As a result, the goal of this research is to efficiently manufacture MOF-polymer composites and synergistically improve the performance of polymer nanocomposites composed of IFR. We firstly proposed our fundamental understanding of how MOFs with different transition metals improve the performance of commercialized IFR based composites, including dispersion efficiency, thermal stability, flammability behaviors, and combustion mechanisms. After determining their potential applications on flame retardancy, we scale up MOF synthesis for our industrial collaborators with a detailed process kinetics and hazard analysis before actual implementation. Some gaps between laboratory-synthesized and commercial-deployed MOF-polymer composites are observed during scale-up study: most MOFs are synthesized in lab in milligram/gram scale under batch reactions and are then used to manufacture composites in a discontinuous process; it requires a large volume of hazardous solvents during the solvothermal synthesis, which posts more environmental issues and increases material costs. To improve the production efficiency, we propose a continuously one-step, rapid, and solvent-free approach to manufacture MOF-polymer composite directly from solid reagents (polymer matrix, metal irons, and ligands) via extrusion that can reach a few kilograms per hour scale compared with conventional method in grams/batch/day. Further LCA studies focus on identifying and studying the sustainability of MOF technology, specifically the potential industrial production at large scales. By comparing the production of 1 kg ZIF-67, reactive extrusion exhibits several orders of magnitude (~3-5) lower than solvothermal reaction in terms of environmental and health impacts. Overall, the outcome of this research can accelerate development of the next generation of polymeric materials with concurrent functionality and enhanced flame retardant performance across industries involving additive manufacturing and composites.