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Author ORCID Identifier

https://orcid.org/0000-0002-4931-6079

AccessType

Open Access Dissertation

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Polymer Science and Engineering

Year Degree Awarded

2021

Month Degree Awarded

September

First Advisor

Alan J. Lesser

Second Advisor

E. Bryan Coughlin

Third Advisor

Yanfei Xu

Subject Categories

Applied Mechanics | Polymer and Organic Materials | Polymer Chemistry | Polymer Science | Structural Materials

Abstract

This dissertation pertains to generating advanced materials using application-based processing techniques. First, billets consisting of PTFE sintering powders are evaluated using Thermomechancal Analysis. It was found that both shape change and volume change are associated with enthalpic and entropic recoil, respectively. These phenomena, due to melting and stored energy during the powder compaction process, were found to be molecular weight dependent. Additionally, kinetics of the recovery and sintering process were found to be slower in blended specimens than pure samples. Next, the creation of graft copolymers by selectively grafting a second polymer to the amorphous fraction of a semi-crystalline polymer in supercritical CO2 is demonstrated. Grafting yields showed an increasing dependence on the polarity of the semi-crystalline polymer used. Upon further characterization of polystyrene-polyamide 6 copolymers, property enhancements such as high glass transition temperatures and the ability to be remelted are elucidated. Additionally, hydrophobicity is tailored by varying polystyrene composition as well as the grafting polymer. Finally, the use of frontally polymerizable epoxide formulations as adhesives is shown. Lap shear and wire pull-out testing demonstrated adhesion to a wide class of materials, including various polymers, metals, and plywood. Boundary conditions and material properties were shown to significantly affect curing behavior and adhesion results, giving rise to various adhesion mechanisms. Additionally, it has been shown that additives can be used to modify the viscosity of the resin and control volatile formation without negatively impacting the adhesion results.

DOI

https://doi.org/10.7275/24162743

Available for download on Thursday, September 01, 2022

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