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Surface modification by corona discharge plasma is one of the most interesting industrial applications for surface modification compared with other techniques which require vacuum conditions. In this work, we have used the corona discharge plasma technique to modify the wettability properties of low density polyethylene (LDPE) film. The effects of this treatment on the surface of LDPE film have been quantified by contact angle measurements, Fourier-transform Infrared Spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy. With these methods, we have determined how the treatment modifies, activates and functionalizes the surface of LDPE film, increasing its hydrophilic behavior, and how the process parameters influence the uniformity and homogeneity of the treated surface. The results obtained show good treatment homogeneity and an improvement of adhesion properties by the functionalization and etching of the film surface.

In this work, surface modification of low density polyethylene (LDPE) film has been carried out to optimize adhesive joints with polyolefin foam for uses in technological applications. LDPE films were modified in a continuous way using corona discharge plasma with different powers, ranging from 200 to 600 W and several film advance rates in the 5-20 m min À1 range. Changes in surface wettability have been studied with contact angle measurements and subsequent solid surface energy calculation. A polyurethane adhesive was used to join the LDPE film to a polyethylene foam. Mechanical performance of the adhesive joints has been determined by T-peel tests and also the aging effects of several hydrothermal conditions have been studied to evaluate the usefulness of these laminate composites in technological applications. Results show that corona discharge powers between 400 and 600 W are suitable in terms of wettability improvement; on other hand, a slight decrease in surface wettability as the film advance rate increases is detected but the overall changes as a consequence of the film advance rate in the 5-20 m min À1 range are small if compared to changes derived from working powers in the 200-600 W range. Adhesive joints offer excellent mechanical performance and good durability in hydrothermal conditions thus being appropriate for technical applications.

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