Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Polymer Science and Engineering

Committee Chair

Jeffrey Wiggins

Committee Chair School

Polymer Science and Engineering

Committee Member 2

Olivia McNair

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

John Misasi

Committee Member 4

Zhe Qiang

Committee Member 4 School

Polymer Science and Engineering

Committee Member 5

James Rawlins

Committee Member 5 School

Polymer Science and Engineering


In this dissertation, relationships between polyphenylene sulfide (PPS) chain structure and melt processing parameters are linked to thermoplastic composite (TPC) properties and mechanical performance. Deviations from linear PPS structure and the formation of branching/crosslinked moieties upon exposure to TPC manufacturing steps presents an opportunity to systematically uncover the interdependencies of melt-state thermal history on polymer rheology, crystallization, crystal structure, and translate these properties to the continuum level. This work first explores unreinforced PPS and how the formation of non-linear chain architectures yield altered rheological states when held at melt processing temperatures. These hindered chains exhibit unconventional crystallization behavior and non-uniform crystal structure. Second, PPS is applied to unidirectional carbon fiber to create TPCs with varied thermal history to test the effects of melt-state degradation of PPS on fusion joined single lap shear strength. Here, rheological and calorimetric techniques are utilized to model future states of PPS degradation during TPC processing and compared to the values when the polymer is applied to carbon fiber and processed. Fusion joined samples prepared from thermally degraded, processed PPS exhibited weaker strength, as polymer reptation and entanglement was impeded by branch/crosslink sites. On the nano scale, PPS loaded with multi-wall carbon nanotubes (MWCNTs) is studied as a potential susceptor film to promote volumetric heat generation during induction welding. PPS/MWCNT displayed melt processing parameter dependent electrical conductivity and nanocomposite morphology. Thermal cycling experiments of PPS/MWCNT revealed the reduction of thermal degradation of PPS in the presence of the nanoparticle reinforcement.

Available for download on Saturday, March 08, 2025