Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Materials Science and Engineering

Committee Chair/Advisor

Dr. Igor Luzinov

Committee Member

Dr. Scott Husson

Committee Member

Dr. Marek Urban

Committee Member

Dr. Philip J Brown


Additive manufacturing, also known as 3D printing, promises a manufacturing revolution for both industry and academic circles. One of the most widely used method of 3D printing is Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF), which requires a thermoplastic filament to be directed towards a heating block and then deposited via extrusion layer by layer to produce a finished part. However, there are significant issues with this technology, mainly a limitation on the materials available for use and mechanical property deficiencies when compared to traditional manufacturing. These issues are brought about by the temperature limited nature of the 3D printed process as well as thermodynamic limits that exist for immiscible polymer systems. To this end, the key goal of this dissertation is the understanding of our polypropylene (PP) and polyethylene terephthalate glycol (PETG) immiscible polymer system as well as the development of three viable methods through which the issues pertaining to multicomponent systems can be resolved.

Namely, we report here on the morphology and structure behind a PPwPETG hybrid filament as well as the introduction of SiC whiskers as inorganic heating elements. First, the PPwPETG hybrid filaments are melt blended, with differences in viscosity and concentration being the controlling parameters behind final structure. These PETG inclusions serve as anchoring agents that utilize fundamental diffusion principles to strengthen the polymer layer interface both independently as well as when printed alongside bulk PETG.

The second part of the dissertation is devoted to the addition of microwave absorbent SiC whiskers, which serve as localized heating elements that extend the amount of time above which polymer chains are able to disentangle and diffuse without damaging the structural integrity of the samples. In the final part of this work, we combine the hybrid filaments with SiCW additions so as to take advantage of the PETG anchoring as well as the additional heating elements. The obtained results show significant improvements for both SiCW materials as well as PPwSiCWwPETG materials following MW treatment.

Overall, this dissertation provides insights into utilizing diffusion principles to circumnavigate the thermodynamic limits that restrict immiscible polymer systems in additive manufacturing. Our understanding of the PP-PETG system as well as the addition of SiC whiskers can not only improve this particular binary system but lays the groundwork for understanding other immiscible polymer systems and expanding the range of 3D printable materials.

Author ORCID Identifier




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