Atmospheric Dielectric Barrier Discharge Treatments of Polyethylene, Polypropylene, Polystyrene and Poly(ethylene terephthalate) for Enhanced Adhesion

A critical review of published studies investigating the dielectric barrier discharge (DBD) treatment of four polymers widely employed in the packaging sector, namely: polyethylene (PE), polypropylene (PP), poly(ethylene terephthalate) (PET) and polystyrene (PS) is presented. The DBD treatment process operates at atmospheric pressure in air, and thereby offers a low cost method of enhancing the surface properties of polymers. The method is suitable for high volume in-line applications such as packaging. It has been reported that treatment doses as low as 0.01 J/cm2 result in significant increases in surface energy and wettability, leading to enhanced adhesive bonding and printing performance. Two critical issues limit the improvements obtained via the DBD processing of polymers. Firstly, DBD processing can produce a poorly adhered surface layer of low molecular weight material, which can then interfere with bonding and printing processes. Secondly, the properties of DBD treated polymers tend to revert towards that of the untreated state during storage.