Date of Submission

5-2026

Document Type

Thesis

Degree Name

Master of Science in Chemical Engineering

Department

Chemistry and Chemical Engineering

Advisor

Huan Gu, Ph.D.

Committee Member

Pier Cirillo, Ph.D.

Committee Member

Eddie Luzik, Ph.D.

Keywords

Polyethylene, polymer functionalization, amide groups, biodegradation, biofilm formation, microbial adhesion, surface chemistry

MeSH

Polyethylenes, Polymers, Amides, Biodegradation, Environmental, Biofilms, Bacterial Adhesion

LCSH

Polyethylene, Polymers, Amides, Biodegradation, Biofilms, Surface Chemistry

Abstract

Polyethylene (PE) is one of the most widely used polymers due to its durability, low cost, and chemical stability; however, these same properties contribute to its persistence in the environment. It takes about 1000 years for PE to be degraded by microbes in nature. This study investigates a molecular design strategy to enhance the biodegradability of PE by introducing polar functional groups into its backbone through palladium-catalyzed copolymerization with a Vince lactam-derived comonomer. This strategy was inspired by our previous observation that PHEVD (poly[7-(2-hydroxyethyl)-2,4-divinyl-3-oxa-7-azabicyclo[3.3.0]octane-6,8-dione]), a newly synthesized petroleum derived polymer that is rich of amide group, can be near-completely degraded by Pseudomonas aeruginosa (PAO1), a microorganism that commonly exists in soil, after a 7-day incubation at 37 °C and atmospheric pressure with shaking at 200 rpm. We hypothesized that we could increase the biodegradability of PE by an amide functionalization. The successful synthesis of the N-Boc protected Vince lactam demonstrated the feasibility of preparing functional comonomers for potential incorporation into PE. Then, 1H NMR analysis indicated comonomer incorporation into the PE backbone. Since the biodegradation of this newly synthesized polymer will be characterized by exposing the polymer to Staphylococcus aureus (SA) and PAO1, microbial biofilm assays were first conducted with another list of chemicals to evaluate how chemical properties influence microbial adhesion and surface colonization. The results showed that several compounds (NSK-012, NSK-013, NSK-014, NSK-015, NSK-016, NSK-018, and NSK-019) inhibited biofilm formation in SA while NSK-012, NSK-013, NSK-015, NSK-016, and NSK-018 exhibited inhibitory effects against PAO1 biofilms, with no significant impact on planktonic bacterial growth, indicating that microbial adhesion can be influenced independently of bacterial viability. These findings provide insight into how surface chemistry regulates microbial interactions and support the hypothesis that incorporation of amide functional groups into PE may facilitate microbial attachment, a critical first step in biodegradation. Although direct degradation of the modified polymer was not evaluated, this work establishes a foundational framework for designing PE materials with improved potential for environmentally assisted degradation.

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