In-situ metallization of polypropylene films pretreated in a nitrogen or ammonia low-pressure plasma

• Published in: Thin solid films 1989-12, Vol.181 (1), p.451-460
• Main Authors: André, V, Arefi, F, Amouroux, J, De Puydt, Y, Bertrand, P, Lorang, G, Delamar, M
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Machinery and processing; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/0040-6090(89)90514-2

The polypropylene films are pretreated in a nitrogen or ammonia low-pressure plasma in order to improve their adhesive properties towards an in-situ deposited aluminium coating. The treatment conditions are similar to industrial ones and treatment times as short as 23 ms allow a considerable improvement of the adhesion between the polypropylene and the aluminium. The aim of this work is to understand better the mechanisms involved in the adhesive phenomena. Indeed, the modifications created by the plasma (for very short treatment times) are not easily detected. SSIMS has revealed the presence of a thin non-homogeneous film of light-weight hydrocarbons on the non-pretreated polymer. This film is responsible for the non-adhesion of the aluminium coating onto the polymer. Actually when this film is removed by a cleaning process induced by the plasma, the interactions between the aluminium and the polypropylene are strong enough to allow a good adhesion. This explains one of the effects of the plasma and more experiments will be carried out in order to determine the key factor of the phenomenon: the role of the oxygen at the interface on the treated polymer will be investigated as well as the diffusion depth of the treating gas.