[en] Complete text of publication follows. The basic idea of our work was to test whether aromatic azides provide a useful tool for photochemical surface modification of PP, yielding covalently bonded amines by insertion of nitrene intermediates into C-H bonds. In previous works we were able to achieve enhanced wettability or light stability of PP surfaces by photochemical immobilisation of azides with hydrophilic and light stabilising residues as 'active' groups (=X), respectively. The aim of the present study was the investigation of the influence of the structure of the azide (i.e. introduction of a spacer enhancing solubility and diffusion) and the polymer modification procedure on the grafting yield. Therefore, azido benzoic esters with aliphatic spacers of different chain length (C₂-C₁₂, X=H) were synthesized and grafted onto PP films, varying reaction parameters such as azide concentration, duration of immersion time in the azide solution, time of UV-irradiation and light intensity. Real-time FT-IR spectroscopy was employed for monitoring the photolysis of the azides. The amounts of adsorbed azide as well as covalently bonded amine were quantified by IR spectroscopy and by UV spectroscopy after extraction. The homogeneous surface distribution of the grafted amines was visualized by FT-IR-microscopy