Molecular Modeling of the Deformation of Polymer Chains
Abstract
The prediction of the mechanical properties of polymer chains has centered so far primarily on the use of empirical potential energy functions, which are limited by the chosen classical force-field. A theoretical evaluation of polymer chain moduli by a molecular orbital approach constitutes a continuing effort of our laboratories. In this study we report the prediction of the strain-dependence of the vibrational frequencies for PPTA as compared to experiment. A negative slope for strain-induced frequency changes in PPTA single fibers is calculated, and also observed experimentally through the use of Raman spectroscopy, of up to ca. -5 cm-1/yields a value of -13 cm-1/that this slope for PPTA fibers is proportional to Young's modulus. This may explain in part our overestimation of these slopes; the fiber is not a single crystal and the predicted modulus is also overestimated by approximately 1.5.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2000
- Bibcode:
- 2000APS..MARL36147A