Surface modification and improved adhesion of wood-plastic composites (WPCs) made with different polymers by treatment with atmospheric pressure rotating plasma jet

Abstract

Because of the low polarity of the polymers used for manufacturing wood plastic composites (WPCs), they have low surface energy and their adhesion properties are limited. In this study, the surface modification with atmospheric pressure rotating plasma jet (APPT) of several WPCs made with different polymers is proposed as an environmentally friendly alternative for increasing their hydrophilicity and adhesion. Both the nozzle-WPC surface distance and the platform speed were varied during APPT treatment and only one pass was carried out. APPT treatment of the WPCs made with polyethylene and polypropylene removed most of the wood component and exposed the polymer to the surface, changing their chemistry, surface energy and topography. An improvement in adhesion of the WPCs to different coatings was obtained which was ascribed to the creation of new polar carbon-oxygen moieties, and the removal of wood component on the WPC surfaces. The less surface modification caused by APPT treatment of the WPC made with poly (vinyl chloride) was ascribed to its low wood content and the presence of inorganic fillers.