(654e) Population Balances for Polymer Upcycling Processes: A Framework for Testing Mechanistic Hypotheses

Polymer upcycling is a potential solution to the abundance and persistence of plastic wastes in the natural environment. This work shows how proposed catalytic mechanisms can be incorporated into population balance models to predict the time evolution of chain length and polydispersity. We will consider models for homogeneous and heterogeneous catalysts, including catalysts that cut randomly, catalysts that cut processively, and catalysts that cut cooperatively. In the case of heterogeneous catalysis, we will discuss the critical importance of adsorption constants that depend on polymer chain length. Finally, using experimental data on polyethylene upcycling, we show how these models can help to interpret experimental data, to test mechanistic proposals, and to extract kinetic parameters.