Polybenzodiazine Aerogels: All-nitrogen Analogues of Polybenzoxazines - Synthesis, Characterization, and their Application in Carbon Dioxide Capture

Author

Vaibhav Edlabadkar, Missouri University of Science and Technology

Abstract

"The rapidly risen concentration of carbon dioxide in the atmosphere over recent years contributed to global warming and ocean acidification. Carbon capture is viewed as an essential tool from keeping atmospheric CO₂ levels from rising further. This thesis focuses on the development of new materials for high capacity and selective adsorption of CO₂. One such material was based on a newly synthesized tetrahydroquinazoline (THQ), which was designed as an all-nitrogen analogue of main-stream benzoxazine monomers. THQ solutions in DMF gelled at 100 °C via HCl-catalyzed ring opening polymerization to polybenzodiazine (PBDAZ) wet gels, which were dried in an autoclave with supercritical fluid CO₂ to aerogels. Those as-prepared PBDAZ-100 aerogels undergo ring-fusion aromatization at 240 °C under O₂. This oxidized form is referred to as PBDAZ-240. Chemical identification of PBDAZ-100 and PBDAZ-240 relied on consideration of all nine possible polymerization pathways, in combination with elemental analysis, infrared, solid-state ¹³C NMR and ¹⁵N NMR spectroscopy of aerogels from selectively ¹⁵N-enriched THQ monomer. Fully oxidized PBDAZ and polybenzoxazine (PBO) aerogels were subjected to pyrolytic carbonization in the range of 300 to 800 °C under Ar to yield carbon aerogels. Subsequently, carbon aerogels were etched at 1000 °C under flowing CO₂ to create microporosity. Etched-PBDAZ carbon aerogels showed very high CO₂ uptake (11.50 ± 0.8 mmol g⁻¹ at 273 K, 1 bar) and high selectivity of CO2 versus H₂ in the range of 397-404, which is attractive for pre-combustion capture of CO₂, as well as high selectivity of CO₂ versus N₂ in the range of 42-48, which is attractive for post-combustion CO₂ capture from flue gas"-- Abstract, p. v

Advisor(s)

Sotiriou-Leventis, Lia

Committee Member(s)

Miller, F. Scott, 1956-
Winiarz, Jeffrey G.
Nath, Manashi
Reddy, Prakash, -2024

Department(s)

Chemistry

Degree Name

Ph. D. in Chemistry

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2025

Pagination

xvi, 183 pages

Note about bibliography

Includes_bibliographical_references_(pages 176-182)

Rights

©2023 Vaibhav Edlabadkar , All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12480

Recommended Citation

Edlabadkar, Vaibhav, "Polybenzodiazine Aerogels: All-nitrogen Analogues of Polybenzoxazines - Synthesis, Characterization, and their Application in Carbon Dioxide Capture" (2025). Doctoral Dissertations. 3380.
https://scholarsmine.mst.edu/doctoral_dissertations/3380