SF/sub 6/ foamed insulation. Final report
Sulfur hexafluoride (SF/sub 6/) epoxy foam, a novel material which consists of a highly electronegative gas (SF/sub 6/) confined in a network of closed epoxy cells is described. SF/sub 6/ epoxy foam can be prepared by mixing liquid epoxy and molecular sieves that have been previously loaded with SF/sub 6/ (molecular sieves adsorb approximately 25% by weight SF/sub 6/). When the mix is heated, the molecular sieves release their adsorbed SF/sub 6/, thus foaming the epoxy. Subsequent cure traps the SF/sub 6/ in small, evenly distributed closed cells. Some of the measured properties of SF/sub 6/ epoxy foam indicate this unique material is suitable for high voltage electrical insulation. These properties include a low dielectric constant, a high dielectric strength, the ability to regain dielectric strength when punctured (by a low power source), and a material that does not require vacuum casting. Since some of these properties can be directly attributed to SF/sub 6/, an analytical method was developed to determine if epoxy foams retained the SF/sub 6/ blowing agent. Neutron Activation Analysis (NAA) was the chosen non-destructive method. Consequently, after measuring a sample's initial SF/sub 6/ concentration, the sample could be aged and reanalyzed in order to measure changes in SF/sub 6/ content due to aging. The NAA data obtained on aged samples indicated that some materials retained SF/sub 6/ up to the point of thermal decomposition, whereas other formulations retained SF/sub 6/ provided they were not aged in excess of their glass transition temperatures. The retention of SF/sub 6/ by these foams suggests they will retain the properties attributed to SF/sub 6/ and they can therefore be used as high voltage insulation in either air of SF/sub 6/ environments.
- Research Organization:
- Gould, Inc., Colmar, Pa. (USA). Research and Development Div.
- OSTI ID:
- 7212947
- Report Number(s):
- EPRI-EL-520
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
EHV & UHV-- (-1989)
24 POWER TRANSMISSION AND DISTRIBUTION
AC SYSTEMS
ACTIVATION ANALYSIS
CHEMICAL ANALYSIS
COLLOIDS
DIELECTRIC PROPERTIES
DISPERSIONS
ELECTRICAL INSULATION
ELECTRICAL PROPERTIES
EPOXIDES
FLUORIDES
FLUORINE COMPOUNDS
FOAMS
HALIDES
HALOGEN COMPOUNDS
HVAC SYSTEMS
MANUFACTURING
MATERIALS TESTING
MEASURING INSTRUMENTS
MECHANICAL PROPERTIES
NEUTRON ACTIVATION ANALYZERS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POWER SYSTEMS
PRODUCTION
SULFUR COMPOUNDS
SULFUR FLUORIDES
TESTING