Alkyl-substituted phenyl ether as a new impregnant for synthetic polymer sheets insulation

As a candidate of impregnant which exhibits better compatibility with polypropylene-based sheets insulation, many kinds of ethers involving phenyl and/or aryl groups are synthesized in laboratory scale to be estimated on their physico-chemical and dielectric properties. Though they surely possess a dielectric absorption due to dipole orientation, their dielectric loss factor is in extremely low level at power frequency above the temperature of −50°C, as far as the sufficient purification is achieved. Taking account of major requirement for cable or capacitor application, selected are nonyl phenetole, hexylphenyl phenyl ether and n-tetradecylphenyl phenyl ether as a promising dielectric. Subsequent determination indicates that three types of aryl ether offer more desirable balance between physical and dielectric properties and favourable compatibility with polypropylene film, rather than dodecylbenzene and polybutene. Consideration is additionally given to their compatibility with polypropylene on the basis of the extended solubility parameter concept.