Plasma processing of polymers for enhanced adhesion to metals and other materials

This paper deals with the plasma surface treatment of polymers in a low fre quency bell jar reactor with non-symmetrical configuration of electrodes. T he highly energetic character of this discharge due to its low excitation f requency 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 t o aluminum, ammonia has shown to be the most suitable one for this applicat ion. Since the NH radicals play an important role in the kinetics of nitrog en incorporation in polymers, mixtures of N-2 and H-2 were also used as pos sible substitutes for ammonia. The former are more environmental friendly t han ammonia. The efficiency of nitrogen rich mixtures in the case of the se cond application i.e. adhesion improvement of copper to fluoropolymers has been compared to that of ammonia which still shows faster nitrogen incorpor ation. The last part of this paper will be devoted to the study of the stab ility of the plasma modified polymers which is an important issue for the i ndustrial development of plasma processes. Plasmas of mixtures of He+NH3 we re studied in order to give rise to stable adhesive properties of PP to alu minum. Finally in this paper examples of industrial surface treatment of po lymers will be given.