The present invention relates to polymer oxidates prepared by reacting polyethylene which has been obtained using metallocene catalysts and which has a weight-average molar mass above 40,000 g/mol with oxygen or oxygen-containing gas mixtures. These polymer oxidates have high suitability for preparing aqueous dispersions, as a material added when dispersing pigments in masterbatches, or for surface-modification or for polar modification of polyolefins. Another advantageous application sector is use as an additive, e.g. as a lubricant for plastics processing.