Characterization of Degraded and Model Post-Consumer Resins to Support Emerging Metrology Needs in Materials Sustainability and End of Life Concerns

To support the development of sustainable polymers and processing methodologies, accurate measurements and quantitative models of polymer structure-property-performance relationships are critically needed to evaluate and compare next-generation materials.  This involves understanding the impacts of molar mass, chemical composition, and architectural distributions of complex polymers to optimize the design of compatibilizers for mechanical recycling, additives for chemical recycling, and degradation lifetimes for polymers in the environment. This talk will highlight efforts to make systematically varied families of model polyolefin compatibilizers and the subsequent characterization of branching content and chain conformation via high temperature size exclusion chromatography. With this information, further characterization of these materials in bulk systems can be studied and results correlated to homogeneous, well characterized materials. Furthermore, for materials designed to degrade, where recovery and recycling is not practical, understanding environmental degradation kinetics on polymer topology and chemistry are crucial to material design.  This presentation will also highlight efforts in our laboratory to study environmental aging of polyolefins with systematic study of chemical, molecular, and thermal properties with material depth to develop improved degradation models as benchmarks for current marine debris. This research can be used to aid in sampling degraded plastic debris and with alternate techniques of identification, quantitative degradation measurements, and (ultimately) information to develop predictive quantitative models of polymer degradation pathways and kinetics in specific ecosystems.