Surface properties and printability of polypropylene film treated by an air dielectric barrier discharge plasma

Abstract

The effect of air dielectric barrier discharge plasma treatment on the chemical structure and morphology of polypropylene (PP) film was studied using UV-VIS (ultraviolet-visible), FT-IR, (Fourier transform infrared), SEM (scanning electron microscopy) and AFM (atomic force microscopy). Polypropylene samples were printed using solvent-based gravure ink. An evaluation of the print quality criteria of the treated PP films included measurement of print density and print gloss. SEM investigated the ink laydown on the modified PP film. The results showed that after a few seconds of plasma treatment, both the surface energy and the surface roughness of the treated PP film increased. There was an increase in the absorbance at the almost-visible range, and C=C and C=O bands were found after the air discharge plasma treatment. A short plasma treatment of 15 seconds was found to bring about a dramatic increase in the print density readings, but a decrease in print gloss. The time of the air discharge plasma treatment was found to have no effect on the print density or print gloss at a high ink film thickness. The results showed that air dielectric barrier discharge plasma treatment, for a few seconds, is effective in printing and is economical for industrial use (this will be studied in detail in future work).