Treatment of polypropylene by dielectric barrier discharge generated at 40 Torr

Abstract

This paper presents the study of DBD generated at a pressure of 40 Torr in a parallel plate electrode system. The main objective of the study was to obtain a stable and homogeneous DBD for uniform treatment of materials. The discharge operating at line frequency (50Hz), voltage 13kV (rms) and pressure 40 Torr was used to improve the wetting properties of polypropylene (PP). The changes in the surface hydrophilicity were investigated by contact angle and surface free energy measurements. The polymer surface morphology and roughness before and after the DBD treatment were analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The PP films modified by plasma treatments show a remarkable decrease in the water contact angle indicating the consequent increase in surface energy. This can be attributed to the introduction of oxygen-containing groups on the surface and the etching of the surface.