Study on Parameter Optimization of Polypropylene Surface Modification in Atmospheric Pressure Dielectric Barrier Discharge

Atmospheric pressure dielectric barrier discharge is widely used for surface modification of polymers. In this paper, the effect of discharge energy density on wettability and oxygen atomic percentage of polypropylene surface is investigated. Contact angle measurement, atomic force microscopy and X-ray photoelectron spectroscopy are applied to analyze the changes of surface wettability and topology of the samples. In the experiments, polypropylene surface contact angles decrease and then increase when the discharge energy density increases. While oxygen atomic percentages increase and then decrease as energy density increasing. An optimum range of discharge energy density is obtained. And it indicates that the changes of water contact angles are due to surface microstructure and chemical compositions by analyzing the results of AFM and XPS measurements. The results show that there exist optimal discharge processing parameters for polypropylene surface modification.