PLASMA-ACTIVATED PACKAGING POLYMER FILMS

The present work is focused on the surface modification of commercial plastic materials used in food packaging and deals with the study of barrier coatings deposited on these modified surfaces, improving their "barrier to gas" performance. The deposited thin coatings are tremendously effective, which makes these materials a valid alternative to coextruded materials, considering both cost and raw materials savings. In fact, the coatings turn out to be equally effective when deposited as a thin layer on common packaging plastics, with the consequent possibility of lightening the pack. Even not much wettable surfaces have been successfully coated after a preliminary surface treatment: surface modifications have been obtained by cold plasma. The study of these surfaces revealed to be particularly interesting: the combined use of several analytical techniques, such as XPS (X-ray Photoelectron Spectroscopy), DCA (Dynamic Contact Angle), and AFM (Atomic Force Microscopy) allowed to interpret the molecular mechanisms that brings to the improvement of surface properties, for what concerns wettability and adhesion by the deposited coatings. An accurate study of the thermal treatments and the high barrier obtained allowed to improve the barrier performance of the common plastic materials used for packaging (food and no-food packaging) and to make savings both in raw materials and in pack weight, with the consequent reduction of waste material to be disposed.