The direct reaction of elemental fluorine with diamonds, YBa$\sb2$Cu$\sb3$O$\sb{\rm 7-x}$, and some unique organic materials has been studied. It has been found that diamonds (powder, slabs, and CVD films) can be directly fluorinated to a small extent using elemental fluorine under various reaction conditions. The reaction appears to proceed by fluorine attacking the diamond's more labile surface features such as the hydroxyl group. While the diamond surface is reactive to some extent, it is difficult to fully fluorinate this surface with elemental fluorine. Plasma fluorination seems to lead to the formation of CF terminal bonds on the diamond surface while high temperature direct fluorination leads to the formation of CF$\sb2$ and CF$\sb3$ terminal bonds. In oxidation resistance studies, the CF$\sb2$ and CF$\sb3$ terminal bonds lead to a more stable product than do the CF bonds.
The direct fluorination of the high temperature superconductor, YBa$\sb2$Cu$\sb3$O$\sb{\rm 7-x}$, leads primarily to the formation of a non-superconducting phase. This phase encapsulates the superconducting phase. Thus, there is no significant change in the fluorinated material's onset of critical temperature, but there is a significant decrease in the degree of magnetic shielding for the material as the amount of fluorination is increased. Initial attempts at synthesizing nitrofluorosuperconductors are presented.
We have successfully used direct fluorination techniques to yield improved properties for Velcro (made principally of polypropylene) and have had some success at fluorinating indan and PVC. The fluoro-Velcro shows enhanced lint repellent properties while maintaining its suppleness and other desirable properties. Perfluoroperhydroindan, a potential fluoroblood, has been prepared in small quantities using this novel treatment. PVC has been modestly fluorinated with the potential of carrying the fluorination to completion and should yield a superior product.
The use of cubic zirconia, an inexpensive diamond simulant, as high pressure/high temperature transmitting windows in the diamond anvil optical cell has been shown to be promising. Pressures nearing 20 kbars can be obtained in the cell using cubic zirconia anvils. The optical properties of cubic zirconia open up a region of the mid-IR that has been inaccessible with previous windows at these pressures. An FT-IR study of the high pressure effects on Fe(CO)$\sb6$($\mu$-CO)$\sb2$($\mu$-CH$\sb2$) is presented as proof. (Abstract shortened with permission of author.)
| Identifer | oai:union.ndltd.org:RICE/oai:scholarship.rice.edu:1911/16279 |
| Date | January 1989 |
| Creators | Patterson, Donald Eugene |
| Contributors | Margrave, John L. |
| Source Sets | Rice University |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | 228 p., application/pdf |
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