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A solid-state NMR study of aromatic polyimides based on 4,4′-diaminotriphenylmethane

✍ Scribed by Antonio Martínez-Richa; R. Vera-Graziano

Publisher
John Wiley and Sons
Year
1998
Tongue
English
Weight
270 KB
Volume
70
Category
Article
ISSN
0021-8995

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✦ Synopsis

The effect of different synthesis routes on the chemical and molecular order of polyimides based on 4,4Ј-diaminotripenylmethane (DA-TPM) and various aromatic dianhydrides (PI-TPM) was studied by solid-state carbon-13 nuclear magnetic resonance ( 13 C-NMR). Polyimides were prepared by three different methods including a two-step procedure with either thermal or chemical imidization of precursor poly(amic acid)s (PAA) and one-step high-temperature polycondensation in phenolic solvents. Model compounds were also obtained and used in the assignment of the NMR signals.

The NMR spectra for PI-TPMs obtained by one-step high-temperature polycondensation and-to a lesser extent-by thermal imidization of PAA, show sharper lines than those observed in the spectra of polymers prepared from PAA via chemical imidization. These differences are due mainly to the lower degree of ordering of the latter polyimides. WAXD patterns of polyimide films also indicated a less-ordered structure of the polymers resulting from the chemical imidization of PAA.

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