The aim of this study was to analyze how corona dosages above recommended levels affect film surface energy and hydrophobic recovery of such treated film surfaces as well as laminate bond strength of laminates made of these films. The adhesive for lamination was a polyurethane-adhesive with a dry film thickness of ∼5 µm. Polar and dispersive parts of the surface energy were measured frequently according to DIN 55660-2 (Owens–Wendt–Rabel-and-Kaelble method) for up to 140 days after corona treatment. The corona dosage had a value of up to 280 W min/m². Laminate bond strength was measured according to DIN 55543-5. The effect of corona treatment was highest for low-density polyethylene (PE-LD) films, mean for biaxial-oriented polypropylene (PP-BO) films, and lowest for biaxial-oriented poly(ethylene terephthalate) (PET-BO) films. With increasing storage time, surface energy decreased, as expected. The higher the effect of corona treatment, the faster the polar part of surface energy decreased. At PE-LD, laminate bond strength increased with a higher corona dosage from 0.05 to 8.87 mN/15 mm, whereas at PET-BO and PP-BO laminate bond strength was so high that samples teared before delamination during bond strength testing. By our results is shown that corona dosages above recommended levels resulted in higher laminate bond strength. Only at PP-BO a reduction of laminate bond strength due to “overtreatment” was be observed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45842. https://onlinelibrary.wiley.com/doi/abs/10.1002/app.45842

For determination of wettability of rough surfaces using the contact angle hysteresis approach and equilibrium contact angles, some new surfaces with controlled roughness were prepared. The influence of the binder nature and size of primary particles of silica powders on surface roughness and wettability of the newlydeveloped films was investigated using optical microscopy, profilometry, SEM and measurement of contact angles of water. Using the silicate binder and silica powders with primary particles of 9 nm, 40 nm and 4 μm, surface hierarchical structures were obtained. The maximal value of the roughness parameter Rq= 366.3 nm was obtained for the sample with silica microparticles of 4 μm. Wettability of the synthesized films was determined mostly by the binder crystals formed on the surface and their ability to interact with hexamethyldisilazane (HMDS). It is well characterised by equilibrium contact angles.

Surface science, which comprises the preparation, development and analysis of surfaces, is of utmost importance in both fundamental and applied sciences as well as in engineering and industrial research. During our research in the field of coatings/surfaces and coating materials, the analyses of wetting of coating materials and the coatings themselves led us to the field of dynamically performed drop shape analysis. We focussed our research efforts on the main problem of the surface science community, which is to determine the correct and valid definition and measurement of contact angles. So we developed the high-precision drop shape analysis (HPDSA) and three statistical contact angle determination procedures. HPDSA involves complex transformation of images from dynamic sessile drop experiments to x-y-coordinates and opens up the possibility of a physically meaningful calculation of curvature radii. This calculation of radii is the first step to an “assumption-free” link to the Laplace equation, which can deepen the understanding of the interface between the liquid and the vapour in relation to different properties and conditions (temperature, experimental technique, surface, etc.). The additional benefit of a tangent-free calculation of contact angles is presented in our 2014 and 2016 published papers. To fulfil the dire need for a reproducible contact angle determination/definition, we developed three procedures, namely, overall, global, and individual statistical analyses, which are based on, but not restricted to, HPDSA . . .

Recent advances in surface science have led to a broad interest in wetting and/or spreading characterization of solid surfaces. Wettability of a solid surface can be defined as the tendency of a liquid to spread over the surface which is measured in terms of an angle, ie, contact angle between the tangent drawn at the triple point between the two phases (liquid and vapor) and the substrate surface. Reproducible and accurate measurements of the contact angle from the experiments are crucial in order to analyze the spreading behavior of a substrate. Spreading is greatly affected by different factors including liquid properties, substrate properties, and system/operating conditions. Here, different types of spreading phenomena in terms of drop evaporation on reactive/non-reactive surfaces and correct measures to obtain accurate contact angles in such scenarios are presented.

Polymers/metal laminates are often used to improve physical and mechanical properties, especially those required in building applications. A flat aluminum composite panel (ACP) consisted mainly of two thin metal sheets usually made of aluminum (Al) and a non-metal core, such as polyethylene (PE). The lack of adhesion associated with the low wettability of PE is a serious problem. An eco-friendly, dry, non-destructive corona treatment technique can be applied to solve this problem. In this work, the use of a corona treatment to enhance the adhesion properties of linear low-density polyethylene (LLDPE) was studied. The changes in surface and adhesion properties were thoroughly analyzed using various analytical techniques and methods to obtain the optimal parameters for corona discharge using contact angle measurements, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). AFM force adhesion measurements were used to analyze the effect of the corona treatment on the adhesion enhancement of LLDPE, and the peel tests confirmed a significant increase in peel resistance in the LLDPE/Al laminate. A synergy effect from using the corona treatment in combination with an ethylene acrylic acid dispersion primer was observed.

This paper, as the title underlines, will be focused on flame treatment technology applications, mainly on BOPP substrates.

After an introduction regarding flame chemistry and BOPP surface activation mechanisms, this paper will be focused on unique flame treatment oxidation performances, in comparison with other treatment methods actually used in the market.

Focus will then be moved to the characteristics and advantages of using flame treatment for film surface treatment. In particular, a comparison will be run with other surface treatment technologies (corona surface treatment and atmospheric plasma treatment) in terms of:

• q surface energy after treatment;
• surface oxidation mechanisms and chemical species involved;
• quantity of oxygen on treated surface (oxidation level);
• quality of oxygen on treated surface;
• adhesion;
• printability/print quality.

Typical and new applications of flame treatment will be presented, underlining benefits coming from flame usage for pretreating different types of skins. Finally, the paper will try to make rid of prejudices and misinformation concerning flame treatment process applications, especially to certain kind of webs and substrates.

In this paper, a polymeric coating based on the modified chlorinated polypropylene (CPP) emulsion was synthesized, methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA) were grafted onto CPP backbone and phase inversion was conducted to obtain waterborne emulsion. Results showed that the concentration of initiator (BPO) had the greatest effect on graft copolymerization. The concentration of emulsifier and temperature influenced the results of phase inversion. Besides, the thermal performances of modified CPP were better than untreated one. In addition, the coating obtained in optimum condition had excellent adhesion to BOPP film, and apparently improved the printing quality of the film. The printability promotion should be attributed to the different movement trend of coating’s polar and un-polar chains during the baking step, as well as the subsequent formations of new coating/substrate and coating/ink interface layer.

Atmospheric pressure plasma treatment of the surface of a polypropylene film can significantly increase its surface energy and, thereby improve the printability of the film. A laboratory-scale dielectric barrier discharge (DBD) system has therefore been developed, which simulates the electrode configuration and reel-to-reel web transport mechanism used in a typical industrial-scale system. By treating the polypropylene in a nitrogen discharge, we have shown that the water contact angle could be reduced by as much as 40° compared to the untreated film, corresponding to an increase in surface energy of 14 mNm⁻¹. Ink pull-off tests showed that the DBD plasma treatment resulted in excellent adhesion of solvent-based inks to the polypropylene film.

Polyethylene (PE) is often used in several industrial applications including the building, packaging and transport industries. Aluminum (Al) is widely used in different applications in the automotive, railway, aeronautic, and naval industries because of its excellent mechanical and chemical properties. Laminates prepared from Al and PE lead to an enhancement in physical and mechanical properties. These materials play a main role in the packaging and building sectors, such as in TetraPak containers and aluminum composite panels. The main problem observed is associated with the adhesion between polymers and metals. This research focused on investigating the enhancement in the adhesion of the PE/Al laminate using the corona discharge. The corona treatment of the surfaces led to a significant increase in the adhesion of the PE/Al laminate as a result of improved surface properties confirmed by peel test measurements. Moreover, the positive effect of the corona treatment in combination with a primer on the improvement of adhesion characteristics was observed too. Different analytical techniques were employed to characterize the effect of the corona treatment on the improvement in adhesion of PE/Al. A significant increase in wettability was confirmed by the measurement of contact angles. Changes in the surface morphology of the PE and Al surface, after the corona treatments at different operating conditions, were observed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). In addition, x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to analyze changes in chemical composition after the corona discharge effect on PE and Al surfaces.