Low temperature thermal properties of composite insulation systems

✍ Scribed by P.E. Fabian; T.S. Bauer-McDaniel; R.P. Reed

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 412 KB
• Volume: 35
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(95)90898-p

✦ Synopsis

The thermal contraction and thermal conductivity of candidate composite insulation systems for the International Thermonuclear

Experimental Reactor toroidal field coils were measured from 295 to 4 K. Matrix materials consisted of a diglycidyl ether of bisphenol-A epoxy suitable for vacuum impregnation, a tetrafunctional epoxy suitable for pre-impregnation, a polyimide system produced by a high-pressure laminating process, and a bismaleimide system. These matrix materials were combined with S-2 glass fabric and various barrier systems, such as ceramic and organic coatings, polyimide film and mica/glass. Thermal contraction was measured by the strain gauge method in which strain gauges are attached directly to the specimen. The thermal contraction in the through-thickness direction was different at 4 K for each resin system and changed slightly with the addition of electrical barriers. The thermal conductivity of the materials, with and without the electrical barriers, was similar at 4 K, but more distinctive at higher temperatures. The systems with the ceramic coatings exhibited the highest thermal conductivities at all temperatures.