HPLC and DSC Analysis of Crosslinked PE from HV Cables

High performance liquid chromatography (HPLC) has beenused to simultaneously determine the amounts of antioxidant(Santonox(R) R), peroxide, acetophenone and ¿-methylstyrenepresent in crosslinked-polyethylene cable samples andmolded specimens, as well as to detect some other peroxidedecomposition products.It was found that the antioxidant is grafted to thepolymer chains after curing (even after partial curing).Results also seem to suggest that a reduction of the phenoliccharacter and perhaps of the effectiveness of thentiantioxidant might result from this grafting process. Peroxidedecomposition products were found to depend on the curingconditions used and to affect the dielectric behavior insome cases.Various XLPE and EPR materials have also been examined bydifferential scanning calorimetry (DSC), and experimentalprocedures were developed for evaluating the degree ofcrosslinking by DSC.This work was part of a program supported by the Electric Power Research Institute.