Dimensional Behavior of Thin-Film Dielectric Polymers in the Temperature Range 4.2 To 300 K
The thermal contraction characteristics of ten commercially available polymeric films considered for superconducting power transmission cable use were evaluated from 4.2 to 300 K. In any candidate tape dielectric/insulator, three parameters are essential in determining a material’s potential applicability. These include the percentage contraction in cooling to 4.2 K, the percentage strain capability at low temperatures, and the dielectric loss behavior. This study has considered the contraction behavior and the degree of anisotropy present in each candidate film. Measurements were made in the long axis of the tape and in the direction of the tape width. No measurements were made through the tape thickness. A tabular summary of tape source, thickness, and tradename appears in Table I.
KeywordsAnisotropy Polyethylene Epoxy Nylon Polypropylene
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