Theses and Dissertations

ORCID

https://orcid.org/0000-0001-7105-3984

Issuing Body

Mississippi State University

Advisor

Smith, Dennis W., Jr.

Committee Member

Pittman, Charles U., Jr.

Committee Member

Toghiani, Hossein

Committee Member

Wipf, David O.

Committee Member

Kundu, Santanu

Other Advisors or Committee Members

Creutz, Sidney

Date of Degree

12-8-2023

Original embargo terms

Embargo 1 Year

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy (Ph.D)

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

This work expands the current understanding of materials chemistry and engineering capabilities of two synthetic platforms: 1.) bis-ortho-diynylarenes (BODA) and 2.) trifluorovinylaryl ethers (TFVE). Each platform possesses a unique chemistry which paradoxically enables the development of high-performance materials therefrom while simultaneously retaining exceptional melt and solution processability. Leveraging the apparent dichotomy in properties (performance/processability) obtainable from these two synthetics platforms, we have pursued and achieved a practical approach to high-temperature resistant materials with an immense potential for technology transfer and commercialization:

1.) BODA-derived resins (BDR) constitute a versatile platform of melt-processable resins capable of rapidly producing high performance matrix composites which include thermoset, carbon-carbon, and other specialty carbon or hybrid ceramic composite structure. BODA monomers can be synthesized via a three-step process from commercially available bisphenols and undergo a facile catalyst-free, thermal-initiated polymerization to yield polyarylene thermosets with outstanding thermal-oxidative stability, low heat release, flame resistance, and high carbon yields (>80%). The combination of melt processability, ease of cure, and high carbon yields in BDR provides an attractive quick, single-step fabrication of carbon/carbon (C/C) composites with excellent interlaminar shear strength (ILSS; ~1800 psi) after a single infusion/carbonization. Furthermore, our work in this area has shown that C/C from BDR can be prepared via a fast carbonization (10 °C/min), relative to typical 1 °C/min or 1 °C/hr industrial carbonizations, without causing undesirable shrinkage, cracking, interlaminar debonding, or detrimental changes in ILSS.

2.) Large polyaromatic hydrocarbons (PAHs) are typically known for their interesting thermal- and photo-optical properties but suffer from poor solubility and processability issues. Functionalization of these moieties with TFVE fluorocarbon groups enables melt or solution polymerization via a thermally initiated [2+2] cyclodimerization of the TFVEs towards high performance perfluorocyclobutyl (PFCB) aryl ether polymers. For example, successful fabrication of free-standing photoluminescent films with record high glass transition temperatures (Tg ~ 300 °C), exceptional thermal-oxidative stability (~250 °C, 24 h), unprecendented photostability at 250 °C in air, and excellent solubility in common organic solvents (at room temperature) have been realized via a set of triphenylene-enchained PFCB aryl ether polymers.

Sponsorship

Battelle, NASA

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