D. Bello, P. Boonruksa, J. Zhang, J. Isaacs, P. Demokiritou, J. Mead
Keywords: CNT, compsosites, polypropylene, polycarboante, epoxy, nanoparticle, performance, toxicity
Summary:The presentation is based on a series of studies designed to investigate the feasibility of end-of-life recycling of CNT-reinforced nanocomposites and its impact on nanocomposite performance, worker exposures, and toxicity of real-world nanoparticle exposures during nanocomposite synthesis, recycling, and end-of-life incineration. A summary of exposures to airborne nanoparticles, carbon nanotubes (CNTs), and fibers generated during various tasks in the injection molding and recycling processes of polycarbonate (PC), polypropylene (PP), epoxy composites reinforced with carbon nanotubes (CNT/PC, CNT/PP, CNT/epoxy, respectively) will be presented. Exposures during processing of neat composites were evaluated for comparison purposes. Multiple metrics were used to characterize exposures, including total number concentration and size distribution from 5.6 nm to 20 µm, nanoparticle and fiber morphology, respirable fiber classification and counting (long and short fibers), CNT quantitation, and integrated sampling for targeted chemical analysis. Similarly, nanocomposite performance was evaluated through serial measurements of structural chemical changes, rheological, thermal, and mechanical properties and crystalline behavior. The presentation will summarize exposure data, explore the impact of recycling on exposures and performance, and discuss implications of these findings for exposure controls, exposure assessment to engineered nanoparticles in complex scenarios, and toxicity testing needs.