Towards circularity: Municipal Solid Waste Valorization and Biobased Polymer Synthesis

Abstract

The research in this thesis primarily focuses on municipal solid waste (MSW) deconstruction and biobased polymer synthesis. The study comprises the following components: (1) optimizing reaction conditions for the deconstruction of mixed waste streams, (2) enhancing the thermal and mechanical properties of polystyrene using biobased monomers, and (3) screening solvent-mediated depolymerization conditions of poly(methyl methacrylate) (PMMA) using thermogravimetric analysis (TGA). The first part of the research investigates the optimization of reaction conditions for deconstructing MSWs. Various parameters, such as temperature, reaction time, and solvent selection, are explored to maximize the efficiency of the deconstruction process. The primary aim is to recover valuable small molecules from the waste stream that can serve as precursors for synthesizing high-value chemicals. The second part explores the hypothesis that functional groups in biobased monomers can enhance polystyrene's thermal and mechanical properties. The selected monomers, derived from renewable sources, are copolymerized with styrene in different mole fractions and characterized to evaluate their thermal properties. The aim is to develop a sustainable approach for improving the performance of polystyrene through integrating biobased materials. The third part of the research focuses on screening solvent-mediated depolymerization conditions for PMMA using an ionic liquid as the solvent to enable circularity in plastic's lifecycle. Different fractions of PMMA in ionic liquid samples are subjected to a range of temperature profiles. Through TGA, the weight loss profiles provide valuable insights into the depolymerization behavior of PMMA. Overarchingly, this thesis aims to contribute to waste management and sustainable materials development by optimizing the deconstruction of mixed waste streams, enhancing the performance of polystyrene through biobased monomers, and screening the depolymerization conditions of PMMA using TGA.