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NMR Analysis of Polyimides

IP.com Disclosure Number: IPCOM000046882D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Jackson, MD: AUTHOR

Abstract

Nuclear magnetic resonance (NMR) spectroscopy is an established technique used by chemists for structure determinations. It can be used to obtain formation of the bulk chemical structure and chain dynamics of polyimides and other nitrogen-containing polymers. One of the primary nuclei of interest has been carbon-13 (13C). Unfortunately 13C spectra of polyimides or, in fact, any nitrogen-containing polymer are not well resolved, especially peaks for carbons attached to nitrogen, due to the quadrupole moment of nitrogen-14 (14N). With poor resolution, it becomes very difficult to obtain detailed information on the chemical structure and chain dynamics of a polymer. This problem might be overcome by using a nitrogen-15 (15N)-enriched (99% atom enrichment) polyimide or other polymer for the solid-state NMR studies.

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NMR Analysis of Polyimides

Nuclear magnetic resonance (NMR) spectroscopy is an established technique used by chemists for structure determinations. It can be used to obtain formation of the bulk chemical structure and chain dynamics of polyimides and other nitrogen-containing polymers. One of the primary nuclei of interest has been carbon-13 (13C). Unfortunately 13C spectra of polyimides or, in fact, any nitrogen-containing polymer are not well resolved, especially peaks for carbons attached to nitrogen, due to the quadrupole moment of nitrogen-14 (14N). With poor resolution, it becomes very difficult to obtain detailed information on the chemical structure and chain dynamics of a polymer. This problem might be overcome by using a nitrogen-15 (15N)-enriched (99% atom enrichment) polyimide or other polymer for the solid-state NMR studies. In the case of 13C spectra of polyimides, 15N offers an advantage over 14N in that it does not possess a quadrupole. It should therefore be possible to obtain 13C spectra in which the quadrupole line broadening effect is not present. Even more important than the reduction of the line broadening in 13C spectra is the fact that 15N possesses a nuclear spin and thus has an NMR signal of its own. By obtaining 15N spectra of polyimides one will be actually probing the site of the imidization reaction, i.e., amide-to-imide conversion. An amide nitrogen will appear at a different location in the 15N NMR spectrum than will the imide nitr...