Date of Award
3-1991
Document Type
Thesis
Degree Name
Master of Science
Department
Department of Engineering Physics
First Advisor
Pete Haaland, PhD
Abstract
The ultimate mechanical properties of polymers, assuming perfect morphology, will be limited by the mechanical properties of a single, ideal polymer chain. Previous calculations of polymer chain moduli using semi- empirical (SE) quantum chemistry methods have resulted in modulus values much higher than experimentally measured. This study investigated the error in the calculated inherent to the method of calculation by comparing SE results for C-C bond potentials in two well characterized polymers, polyethylene and polydiacetylene. It was found that the SE calculation systematically overpredicted bond stiffness in these polymers by approximately 25% to 30%. This is the upper limit on the modulus overprediction, depending on the importance of bond extension/compression (as compared to other deformation modes) in the overall deformation of the polymer chain.
AFIT Designator
AFIT-ENP-GNE-91M-9
DTIC Accession Number
ADA238682
Recommended Citation
Shoemaker, James R., "An Assessment of the Accuracy of Semi-Empirical Quantum Chemistry Calculations of the Mechanical Properties of Polymers" (1991). Theses and Dissertations. 7825.
https://scholar.afit.edu/etd/7825