Record Details
The normal vibrational analysis of polyacetaldehyde
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | The normal vibrational analysis of polyacetaldehyde |
| Names |
Lee, Dorothy
(creator) Decius, John C. (advisor) |
| Date Issued | 1964-12-04 (iso8601) |
| Note | Graduation date: 1965 |
| Abstract | A method of calculating the normal vibrations of polymer molecules is presented in detail. The method is based on that used by Schachtschneider and Snyder in their analysis of polypropylene but has not heretofore been published. The factoring of the infinite matrix and reduction to the coordinates of the unit cell is justified in a manner based on the factoring of finite molecules. It is comparativeIy simple for anyone familiar with the method of calculating the normal vibrations of finite molecules to make the extension to polymer molecules by this method. The geometry of polymer chains is discussed in connection with setting up the g matrix for the calculations. Some errors in the use of the geometric relationships of Shimanouti and Mizushima on the helical configuration of polymer chains are pointed out and supplementary relationships are presented. Some arguments in favor of the valence force field for this type of calculation are discussed. The error inherent in using the equilibrium transformation between the valence and Urey-Bradley force field is pointed up and made more obvious in a calculation of the normal vibrations of trioxane. In this calculation the polyether force constants reported by Tadokoro for polyoxymethylene gave a very poor fit of the data. Transference of the valence force constants obtained in the trioxane data to polyacetaldehyde gave as good a fit for polyacetaldehyde as was obtained in the trioxane calculation. The method developed in the first chapters of the thesis for the norrnal vibrational analysis of polymers is applied to polyacetaldehyde in the last chapter. It is not possible to adjust the force constants to fit the observed frequencies because of the large number of calculated frequencies and force constants compared to the small number of observed frequencies. It appears to be possible to make band assignments in agreement with the calculated frequencies if reasonable force constants are already available. |
| Genre | Thesis/Dissertation |
| Topic | Acetaldehyde |
| Identifier | http://hdl.handle.net/1957/48078 |
