Investigation of long-term stability of an atmospheric pressure plasma treatment of plastic melts

• Main Authors: Burandt, Pia, Schiffers, Reinhard
• Format: Conference Proceeding
• Language: English
• Subjects: Adhesion; Adhesives; Atmospheric pressure; Chemical bonds; Contact angle; Extrusion dies; Polymer films; Raw materials; Stability; Surface tension
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0168542

Plastic films make a valuable contribution in many areas due to their economic and technical advantages. To meet the associated requirements, complex combination of film properties must be achieved. For this purpose, varied materials are combined with each other. However, to ensure the overall function in use, the individual layers in the films must not separate from each other. The long-term stability can be seen as an important quality criterion for the composite. For a successful bond, the surface tension should be as high as possible at the interface and consist of equal disperse and polar fractions. However, there are material-specific differences. As a result, a bond between the partners is often not possible or it dissolves after a certain initial adhesion. In practice, this is often remedied by primers and adhesives that create a chemical bond between the materials. This use is associated with disadvantages, for example, there are increasingly stricter requirements due to new restrictions on the use of raw materials used in the primers and adhesives. The presented approach in this work to overcome these deficits is to treat the plastic melt of the partner with lower surface tension as it leaves the extrusion die with atmospheric pressure plasma and use it for a film composite free of adhesion agents and adhesives. The focus of the investigations presented here is on long-term stability of the activation effect. For this purpose, the produced samples were stored for up to 504 h. This was accompanied by a contact angle measurement to determine the surface tension according to the Owens-Wendt-Rabel-Kaeble method and an Infrared Spectroscopy to detect chemical changes. It was shown that the plasma treatment was successful on the one hand, but that the associated activation decreased over time. The initial state was not reached again.