Permanent Inhibition of Water Tree Growth in Polyethylene

A solid organic material desirable for use as extruded electrical insulation on underground power cables should provide̲in addition to the expected good electrical, chemical, and physical properties- permanent resistance to the pre-electrical breakdown mechanism called "treeing". Screening of numerous families of materials has revealed many agents which, as additives, confer temporary resistance to treeing upon polyethylene. However, the search for non-migratory, non-volatile additives has proved long and difficult. Other approaches which provide permanent resistance to water and electrochemical tree growth are reported here.