Article
Thermal and Rheological Properties of a Liquid-Crystalline Polyurethane
Macromolecules
(1989)
Abstract
A novel liquid-crystalline polyurethane (LCPU) was synthesized by the condensation of
2,4-toluenediisocyanate and 4,4'-bis(6-hydroxyhexoxy)biphenyl. Solution polymerization in dimethylformamide
produced intrinsic viscosities in the range 0.30-0.57 dL/g. Differential scanning calorimetry shows a crystalline
melting transition that is highly dependent on molecular weight and thermal history and a clearing transition
that is virtually independent of both. Parallel-plate rheometry results are consistent with the presence of
a liquid-crystalline phase, coexisting with a small amount of three-dimensional crystallinity, between 152 and
166 °C. Dynamic mechanical measurements reveal an unusually high elastic modulus of 180 MPa in the plateau
region above Tg, compared with 6 MPa for an amorphous polyurethane with a chemical structure based on
1,4-butanediol.
Keywords
- Thermal,
- Rheological,
- Liquid-Crystalline,
- Polyurethane
Disciplines
Publication Date
1989
Citation Information
William MacKnight, Peter J. Stenhouse, Enrique M. Valles and Simon W. Kantor. "Thermal and Rheological Properties of a Liquid-Crystalline Polyurethane" Macromolecules Vol. 22 (1989) p. 1467 - 1473 Available at: http://works.bepress.com/william_macknight/253/