Publication details
Comparative study for investigation of BOPP foil surface treatment by different atmospheric-pressure plasma sources
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| Year of publication | 2021 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| Description | For polymer materials surface treatment, cold atmospheric plasma is widely used [1]. Polypropylene (PP) is a famous type of polyolefin used in a wide variety of applications. Although the biaxially oriented polypropylene (BOPP) films have many advantageous properties, their applications have limitations due to the poor adhesion properties resulting from their non-polar nature and low surface energy [2,3]. In this comparison study, the 25 ?m thin BOPP film was treated by plasma generated by three different atmospheric-pressure plasma sources, specifically by diffuse coplanar surface barrier discharge (DCSBD) with the concavely curved electrode installed in the roll-to-roll reactor [4], plasma jet array (Fig. 1) [5], and multi-hollow surface dielectric barrier discharge (MSDBD) [6]. DCSBD was generated in ambient air by supplying the sinusoidal high voltage with the amplitude of 10 kV and the frequency of 15 kHz at the plasma power density of 2.5 W/cm2 corresponding power 400 W. The plasma jet array was operated in argon used as the working gas. The supplying voltage was of the sinusoidal waveform with 8 kV peak-to-peak value and of 23 kHz frequency at power 12 W. In the case of MSDBD used as a plasma source for the treatment, the voltage amplitude was 7 kV, and the frequency was 27 kHz at 30 W power. During the plasma treatment, the following distances between treated BOPP film and plasma sources were kept: 0.3 mm from the curved ceramics of DCSBD, 50 mm from the plasma jet nozzle, and 0.3 mm from the perforated ceramics of MSDBD. The samples were treated by plasma for the exposure times 1 s, 3 s, 5 s, 10 s. The surface wettability of BOPP film treated by all plasma sources was investigated by measuring the water contact angle (WCA) immediately after treatment, and for DCSBD and plasma jet treatment also after 1 and 3 weeks later to study the stability of the treatment and the possible ageing behavior. Furthermore, Attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR) for characterization of the plasma-induced chemical groups changes on the surface, the profilometer/roughness gauge for roughness measurement, and scanning electron microscopy (SEM) for BOPP film surface morphology investigation were used and the results were compared. The best WCA values immediately after treatment were shown for the treatment by plasma jet with 10 s exposure time. However, the most stable treatment was confirmed for DCSBD plasma treatment with the 5 second exposure time. The results of SEM and roughness measurement of the BOPP film surface after DCSBD and plasma jet treatments were very similar. |