| Description |
Polymers are distinguished by their low density, flexibility, ease of manufacture, and cost- effectiveness. One of the most used polymers in a wide variety of applications is polypropylene. Biaxially oriented polypropylene (BOPP) has many significant properties, including chemical resistance, excellent optical properties, high strength, lightweight, and exceptional moisture barrier properties. For these reasons, BOPP films are using commonly in the electrical industry to produce capacitors and food packaging. However, there are some limitations to using the BOPP film in composite and laminated materials and printing, dyeing, and coating industrial areas, in which, from an environmentally friendly point of view, water-soluble inks and solutions are used. This fact is a consequence due to the innately hydrophobic and low-surface energy character of polypropylene. For these reasons, it is necessary to increase BOPP film's wettability and adhesion properties without changing the bulk properties [1,2], which can be achieved by its surface treatment. Among the many surface treatment technologies, the cold atmospheric-pressure plasma represents an efficient and modern method for surface modification mainly due to the advantages of short exposure times, fast speed, simple operation, and easy control [3]. In our comparative study, the thermally sensitive BOPP film was treated by different atmospheric-pressure plasma sources for 1, 5, and 10-second exposure times and in different working gases. The plasma sources included nitrogen MSDBD [4], a linear nitrogen DCSBD-based plasma system, an argon cylindrical plasma jet array [5], and a DCSBD generated in ambient air and nitrogen gas [6]. The water contact angle (WCA), SEM, Profilometer, and XPS analyses were used to determine the wettability, morphology, and surface chemical composition of the BOPP plasma treated film. The adhesion properties were evaluated by the peel force measurement. The most significant change in the WCA reaching the value of 37.9 °compared to 100.8 °for the reference sample was obtained immediately after the linear nitrogen DCSBD-based plasma system treatment. Moreover, the adhesion increased by approximately 4 times after plasma treatment, mainly using DCSBD generated in air.
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