CAREER: Flavones as safe, sustainable additives to tune biodegradable plastic stability

Plastic pollution is a global threat to human and environmental health. During everyday use and weathering, plastics breakdown and release highly toxic plastic additives. There is an urgent need for safe plastic additives. In this project, flavones, a class of natural chemicals found in plants and food, will be explored as sustainable plastic additives. Flavones are excellent candidates for light stabilizer additives and can kickstart plastic breakdown. This project will address the end-of-life management of plastics. Research outcomes will create: 1) safe alternatives to the toxic plastic additives that are currently in use; and 2) solutions to enhance the breakdown of biodegradable plastics to minimize plastic pollution. The project will provide educational opportunity to train the next generation of environmental engineers. The overall goal of this CAREER project is to advance flavones as sustainable plastic additives to enable the tuning of biodegradable plastic stability and persistence. A major focus is to understand how flavone chemical structure impacts fundamental photophysical and photochemical properties. The project will first evaluate flavones as light stabilizers in biodegradable plastics. Flavone functional groups that control light absorber properties will be identified by exploring the fundamental photophysical pathways of flavones with spectroscopy and reactive chemical probes. Key stabilization performance metrics will be evaluated with an array of materials characterization, chemical analysis, and aquatic toxicity testing to understand flavones’ 1) ability to stabilize biodegradable plastics; 2) photostability within biodegradable plastics; and 3) ecological effects. Finally, the project will evaluate flavones as pro-oxidants to increase biodegradable plastic deterioration. Overall, this CAREER project will advance flavones as sustainable plastic additives, opening the door to a new class of non-toxic additives derived from renewable resources. More broadly, it will advance light-triggered, pro-oxidant additives as an avenue to enhance biodegradable plastic deterioration in slow degrading environments such as surface waters. This project will enhance student training in sustainable chemistry with a focus on circularity, the end-of-life management of materials, and toxicity reduction and hazard prevention through 1) enhancing environmental engineering coursework; 2) connecting students to industry perspectives on sustainability; and 3) introducing sustainable chemistry to high school STEM students through outreach. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.