RADIATION PROCESSING OF POLYMER INSULATORS - A METHOD FOR IMPROVING THEIR PROPERTIES AND PERFORMANCE

Polymer insulators for electric apparatus and high-voltage overhead li nes are promising for replacing porcelain and glass insulators. The po ssibility of this application is shown by radiation-chemical technolog y for the manufacture of rod-shaped polymer insulators. An ethylene an d vinyl acetate copolymer (EVA) was used as the basis for polymer insu lators. The composition also contains aluminium hydro;dde as a filler and N,N'-m-phenylene dimaleimide as a sensitizer. The investigation of gamma-radiation-induced crosslinking of this composition made it poss ible to establish the following optimum conditions of radiation proces sing of insulators: the absorbed dose of up to 200 kGy at a dose rate of 10 kGy/h in air. By forming a three-dimensional network in the poly mer bulk by radiation, the service properties of the insulators are im proved: Shape and heat stability is >200 degrees C and the stability t o tracking and erosion >200 h. Differential scanning calorimetry (DSC) and a method of stress relaxation were used in evaluation. In the Sai nt Petersburg region (Russia), several types of high-voltage (10-110 k V) polymer insulators are manufactured with the application of such ra diation-chemical technology.