Adhesion of Polyethylene to Copper: Reactions between Copper Oxides and the Polymer

Abstract

In order to get good adhesion between polyethylene and copper previous workers have oxidised the metal in an alkaline solution to give a matt black oxide layer. It was thought that the good adhesion was a consequence of copper (II) oxide in this layer oxidising the polymer and being reduced to copper (I) oxide in the process. In this paper, changes in oxide composition during bonding by melt coating at 200° C were followed by coulometric reduction supported by x-ray and electron diffraction. It is shown that for coating times required to get good adhesion, the changes of composition of the oxide film are not the result of interaction with the polymer. The change from the higher to lower oxide is probably due to reaction with the base metal: CuO + Cu→ Cu₂O