Date of Award

12-2025

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

School

Polymer Science and Engineering

Committee Chair

Zhe Qiang

Committee Chair School

Polymer Science and Engineering

Committee Member 2

Derek Patton

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

Jeffery Wiggins

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Sergei Nazarenko

Committee Member 4 School

Polymer Science and Engineering

Committee Member 5

Monica Tisack

Abstract

Though tremendous progress has been made engineering carbon materials across length-scales from the molecular to the macroscopic, on-demand macro-structural control of carbons is still developing. Many carbon materials like graphene, carbon nanotubes, activated carbons, and carbon fibers have powder or fiber form factors. Recent research has pioneered on-demand carbon production through additive manufacturing (AM) via 1) extrusion and post-processing of highly filled carbon slurries, or 2) printing and pyrolysis of polymeric carbon precursors such as polyimides, acrylated polyethylene glycol, and phenolics. While groundbreaking, most methods face challenges with adoption due to costly/complex materials and manufacturing processes, and large dimensional changes during processing. This dissertation establishes a scalable platform for carbon AM using fused filament fabrication (FFF) of polyolefin precursors and sulfonation-induced crosslinking. The first work (chapter two) elucidates a crack-assisted diffusion mechanism during crosslinking, enabling rapid crosslinking of thick, printed samples. Utilizing this mechanism, printed polypropylene structures act as efficient carbon precursors, retaining their printed geometries and displaying anisotropic shrinkage/mechanical behaviors resulting from their FFF printed nature. Resulting carbons displayed efficient Joule heating behavior, and the process was adaptable to post-consumer precursors. Chapter three expands precursor selection, investigating polyethene precursors which display smoother morphologies than polypropylene while achieving improved reaction kinetics at lower temperatures. This enables enhanced mechanical properties which may be improved through carbonization conditions. The fourth chapter examines chopped fiber-containing polypropylene filaments as carbon precursors. Carbon fiber inclusions enhanced cracking/diffusion phenomena, enabled near net-shape conversion of printed precursors to carbons, and allowed for tunable, even reversibly compressible, mechanical properties based on controlled macroporosity. Chapter five investigates the role of rigid fibers in polypropylene precursors where glass fiber inclusions resulted in more rapid crack formation, reduced dimensional shrinkage, and enhanced mechanical properties at high loadings. Chapter six leverages 3D printed carbons for electrified chemical synthesis of hydrogen through Joule heated ammonia decomposition. This work reports in-situ loading of catalytically active metal nanoparticles from widely available nitrate-salt precursors. Simple processing handles allow for tunable metal loading, morphology, and modular nanoparticle identity. The resulting composites display enhanced catalytic performance and reduced energy of activation for high temperature chemical synthesis.

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