This paper deals with the plasma surface treatment of polymers in a low frequency bell jar reactor with non-symmetrical configuration of electrodes. The highly energetic character of this discharge due to its low excitation frequency and electrode configuration, as well as its small discharge volume makes it a very efficient and fast functionalization process. Amongst the different plasma gases used for the adhesion improvement of polypropylene to aluminum, ammonia has shown to be the most suitable one for this application. Since the NH radicals play an important role in the kinetics of nitrogen incorporation in polymers, mixtures of N2 and H2 were also used as possible substitutes for ammonia. The former are more environmental friendly than ammonia. The efficiency of nitrogen rich mixtures in the case of the second application i.e. adhesion improvement of copper to fluoropolymers has been compared to that of ammonia which still shows faster nitrogen incorporation. The last part of this paper will be devoted to the study of the stability of the plasma modified polymers which is an important issue for the industrial development of plasma processes. Plasmas of mixtures of He+NH3 were studied in order to give rise to stable adhesive properties of PP to aluminum. Finally in this paper examples of industrial surface treatment of polymers will be given.