Accession Number:

ADA250977

Title:

New Thiophene-Based Materials

Descriptive Note:

Technical rept.,

Corporate Author:

NORTH CAROLINA UNIV AT CHAPEL HILL DEPT OF CHEMISTRY

Report Date:

1992-05-20

Pagination or Media Count:

4.0

Abstract:

Our research is focused on the general synthesis of a new class of high performance aromatic thermoplastic and thermosetting engineering polymers from thiophene-based monomers. We are interested in the introduction of changes in polymers by an explicit geometric perturbation of the primary structure of the polymer chain substituting various amounts of thiophene into several classes of phenylene-based polymers. The anticipated property enhancements stem from unique molecular geometry of the aromatic 2,5-thiophene moiety its nonlinear structure with an exocyclic bond angle of 148 deg is intermediate between that of 1,4-phenylene 1 80 deg and 1,3-phenylene 1 20 deg commonly used to prepare high performance materials. Often, the former are difficult to process and the latter exhibit poor mechanical properties. By focusing on the intermediate geometry of the thiophene moiety, we anticipate larger thermal processing windows without losing the desirable crystalline and liquid crystalline properties associated with the 1,4-phenylene-based materials. In addition, the bilateral asymmetry of the heterocycle will certainly influence the melting points, rates of crystallization, glass transition temperatures, solubility, miscibility with other polymers, adhesion, etc. relative to conventional phenylene-based materials. Our investigations of several distinct classes of polymers thiophene-based polyesters, polyaramids, polybenzoxazoles, polyarylene ether ketones, and polyimides via the combination of a new route along with established methodologies will be presented.

Subject Categories:

  • Organic Chemistry
  • Polymer Chemistry
  • Crystallography
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE