Mechanical and dielectric assessment of ultrahigh molecular weight polyethylene insulation for cryogenic applications

In order to test the feasibility of applying ultrahigh molecular weight polyethylene (UHMW PE) as the electrical insulation at cryogenic temperatures, mechanical and dielectric assessment was carried out. In particular, the stress cracking resistance and treeing resistance of UHMW PE at 77 K were tested in comparison with those of crosslinked polyethylene (XLPE) and low density polyethylene (LDPE). The test result and theoretical analysis show that mechanical forces play a dominant role both in stress cracking of LDPE and XLPE, and in electrical treeing at low temperature. UHMW PE with extreme stress cracking resistance is recommended as an appropriate candidate for electrical insulation at low temperature