Generation of crystallographic packing candidates with fixed helical symmetry and axial advance: Application to PI-2 polyimide
- Univ. of Akron, OH (United States)
A normal coordinate approach was used to generate crystallographic packing candidates of a multitorsional polyimide synthesized from 3,3`,4,4`-benzophenonetetracarboxylic acid (BTDA) and 2,2-dimethyl-1,3-(4-aminophenoxy) propane (DMDA) (PI-2). Candidates were obtained under conditions of fixed axial advance of 24.6 {Angstrom} per monomer, and imposed 2/1 helical or 1/0 translational symmetry, consistent with the observed WAXD meridional layer line spacing. The ability of combinatorially generated torsional states to adopt the desired geometry was examined. Necessary corrections to the conformational parameter equations have been made. The procedure described allowed crystallographic conformations satisfying explicit geometric and MM3 intramolecular energy criteria to be generated for a linear multitorsional polyimide prior to the application of crystallographic screening or refinement procedures. 20 refs., 7 figs., 1 tab.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 369850
- Report Number(s):
- CONF-9408178--
- Journal Information:
- Advances in X-Ray Analysis, Journal Name: Advances in X-Ray Analysis Vol. 38; ISSN AXRAAA; ISSN 0376-0308
- Country of Publication:
- United States
- Language:
- English
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