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Glassy carbons from poly(furfuryl alcohol) copolymers: structural studies by high-resolution solid-state NMR techniques

Eckert, Hellmut and Levendis, Yiannis A. and Flagan, Richard C. (1988) Glassy carbons from poly(furfuryl alcohol) copolymers: structural studies by high-resolution solid-state NMR techniques. Journal of Physical Chemistry, 92 (17). pp. 5011-5019. ISSN 0022-3654 . http://resolver.caltech.edu/CaltechAUTHORS:20150805-105521104

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Abstract

The chemical structure of glassy carbon particles produced from poly(furfuryl alcohol) copolymers is studied by ^(13)C cross-polarization/magic-angle spinning (CP-MAS) NMR and high-speed ^1H MAS NMR. In agreement with earlier proposals, ^(13)C NMR spectra confirm the buildup of a highly unsaturated system at the expense of furan rings and aliphatic carbon atoms, and upon heating to 800 K this conversion is essentially complete. Successive carbonization by air oxidation or pyrolysis at temperatures up to 1600 K is reflected in a gradual decrease of the ^(13)C chemical shift from ca. 130 to 115 ppm versus tetramethylsilane. ^1H MAS NMR is used to detect and quantitate the amount of residual C-bonded hydrogen species at various stages of the carbonization process. In addition, these spectra show intense, narrow resonances due to sorbed H_2O molecules, which resonate over a wide range of chemical shifts (between 2.5 and -8 ppm versus tetramethylsilane). In analogy with effects observed by Tabony and co-workers for molecules adsorbed above the basal plane of graphite, the upfield shifts observed for water sorbed in the glassy carbons of the present study are attributed to the large susceptibility anisotropy of submicroscopically ordered, turbostratic, or partially graphitized regions of the samples. The extent of this ordering is inversely correlated with the absolute content of residual C-bonded hydrogen species and depends mainly on the temperature of pyrolysis, whereas the oxygen content of the heating atmosphere and the composition of the initial polymeric material appear to be of secondary importance. The results suggest that sorbed H_2O molecules can function as sensitive NMR chemical shift probes for the initial stages of crystallization processes in glassy carbons.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/j100328a037DOIArticle
http://pubs.acs.org/doi/abs/10.1021/j100328a037PublisherArticle
ORCID:
AuthorORCID
Flagan, Richard C.0000-0001-5690-770X
Additional Information:© 1988 American Chemical Society (Received: January 25, 1988) The NMR data were partly obtained at the Southern California Regional NMR Facility, supported by NSF Grant CHE84-40137. The materials preparation and characterization was supported by U.S. Department of Energy University Coal Programs Grant No. DE-FG22-84PC70775. We are grateful to Larry Henling for performing the elemental analysis of the materials.
Funders:
Funding AgencyGrant Number
NSFCHE84-40137
Department of Energy (DOE)DE-FG22-84PC70775
Record Number:CaltechAUTHORS:20150805-105521104
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20150805-105521104
Official Citation:Glassy carbons from poly(furfuryl alcohol) copolymers: structural studies by high-resolution solid-state NMR techniques Hellmut Eckert, Yiannis A. Levendis, and Richard C. Flagan The Journal of Physical Chemistry 1988 92 (17), 5011-5019 DOI: 10.1021/j100328a037
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59211
Collection:CaltechAUTHORS
Deposited By: Irina Meininger
Deposited On:09 Sep 2015 19:51
Last Modified:09 Sep 2015 19:51

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