Date of Award
Summer 2025
Document Type
Open Access Dissertation
Department
Chemistry and Biochemistry
First Advisor
Chuanbing Tang
Second Advisor
Sheryl L. Wiskur
Abstract
Polyethylene (PE) and polystyrene (PS) are among the most widely produced commodity plastics, yet their persistence in the environment poses a significant challenge to sustainability due to their non-degradable nature and poor recyclability. This dissertation presents the design, synthesis, characterization, and recycling potential of degradable polymer mimics of PE and PS while retaining desirable mechanical properties and enabling closed-loop recycling. First, a model study was developed to access functionalized PE mimics through ring-opening metathesis polymerization (ROMP) and thiol–ene chemistry. By adjusting the ester-to-methylene and branch-to-methylene ratios, a series of high-performance polymers was prepared, exhibiting mechanical properties comparable to HDPE and LDPE. Second, a class of long-chain aliphatic poly(ester)acetals (PEAc) was synthesized from biobased monomers via a polycondensation and polytransacetalization. These polymers demonstrated orthogonal degradability through selective degradation under varied pH conditions and presented strong adhesive properties, enabling distinctive “oligomer–polymer–oligomer” closed-loop recycling. Finally, a new strategy of degradable PS mimics was studied by incorporating degradable ester functionality into the polymer backbone. These PS mimics synthesized via oligomer-based step growth, retained the mechanical properties of commercial PS while showing degradability. Collectively, these studies introduce promising routes for the development of tunable performance, recyclable alternatives to traditional plastics.
Rights
© 2025, Xiaomeng Li
Recommended Citation
Li, X.(2025). Sustainable Polyethylene and Polystyrene Mimics: Design, Degradability and Closed-Loop Recycling. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/8517