Abstract The application of compounds depends strongly on the adhesion between the parts. The subject of interest in this paper is a polypropylene copper compound. Enhancement of the adhesion of the compound can be realized by modifying the polymer surface, e.g., by mechanical grinding, by low-pressure plasma treatment (nitrogen, oxygen, argon) and by generating intermediate layers (polythiophene and plasma-polymerized acrylic acid). The modified surfaces were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and measurements of the surface tension, surface resistance and roughness. The bonding strength was determined by the pull-off test (DIN ISO 4624). Mechanical roughening showed a positive effect on adhesion, but the maximum bonding strength was limited to 1 MPa. The low-pressure plasma treatment with the noble gas argon led to an increased surface tension (γ=57 mN m−1) and thereby to enhanced adhesion. The intermediate polythiophene layer had a moderate influence on adhesion whereas the plasma-polymerized acrylic acid layer contributed excellently to adhesive forces. A combined modification of grinding and an intermediate layer of plasma-polymerized acrylic acid led to an increased bonding strength of 3 MPa.