Date of Award
8-2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
School
Polymer Science and Engineering
Committee Chair
Dr. Jeffrey Wiggins
Committee Chair School
Polymer Science and Engineering
Committee Member 2
Dr. Olivia McNair
Committee Member 2 School
Polymer Science and Engineering
Committee Member 3
Dr. Sarah Morgan
Committee Member 3 School
Polymer Science and Engineering
Committee Member 4
Dr. Sergei Nazarenko
Committee Member 4 School
Polymer Science and Engineering
Committee Member 5
Dr. Derek Patton
Committee Member 5 School
Polymer Science and Engineering
Abstract
Dynamic covalent networks, especially vitrimers, have garnered the attention of the polymer science community due to their unique material properties, which resemble both traditional non-dynamic cross-linked thermosets and traditional linear thermoplastics. Unlike traditional cross-linked networks, vitrimers undergo topological rearrangement upon the application of force at elevated temperature. This aspect enables both malleability and weldability similar to traditional thermoplastics above the glass-transition temperature, providing potential for application as a more environmentally sustainable alternative to traditional thermosets.
The occurrence of topological rearrangement in vitrimers imparts unique rheological properties, evident in their ability to flow and relax stress at elevated temperatures. The influence of network structure on topological rearrangement is complex, which contributes to the increased difficulty of establishing structure-property relationships in vitrimers when compared to traditional non-dynamic polymer networks. As a result, the usage of modular synthetic platforms for intentional variation of network structure is incredibly advantageous for rheological investigations in vitrimers.
Polybenzoxazines are a class of polymers that provide synthetic modularity, enabling the preparation of polymer networks with significant, intentional variation in polymer structure. Previous work established imine-containing polybenzoxazine networks, which demonstrated significant synthetic modularity and enabled thorough structure-property comparisons. Herein, the previously established platform is leveraged for further examination of how structure influences the networks’ rheological properties. Specifically, stretched exponential fitting was applied to the stress relaxation behavior of the networks, indicating the deviation of each network’s stress relaxation behavior to that of the Maxwell model. Additionally, the time-temperature superposition principle was applied to the behavior of the networks in stress relaxation and small-amplitude oscillatory shear experiments. The results indicated that the influence of structure on estimated apparent energy of activation varied non-uniformly according to the timescale corresponding to the estimate, which illustrates the significant complexity of structure-property relationships in dynamic polymer networks.
Copyright
John J. Peyrefitte, 2026
Recommended Citation
Peyrefitte, John J., "Dynamic Properties of Imine-Benzoxazine Vitrimer Networks" (2026). Dissertations. 2492.
https://aquila.usm.edu/dissertations/2492