KINETIC FEATURES OF PLASMA-CHEMICAL MODIFICATION OF POLYCARBONATE IN PLASMA IN ARGON - OXYGEN MIXTURE

Abstract

This paper presents the results of experimental study of the processes of destruction and changes in the composition of the surface layer of a Lexan 8010 polycarbonate (PC) film during treatment in a positive column of a DC glow discharge in argon, oxygen, and their mixtures. The mass loss rates of the polymer samples were measured depending on the parameters of the discharge and the composition of the plasma-forming gas. The IR spectra of the polymer films after plasma exposure were analyzed. It was shown that the most noticeable changes in the sample destruction rate and the chemical composition of the surface layer occur when the oxygen content in the mixture is up to 20%. With a further increase in the O2 content in the plasma-forming mixture, the changes are insignificant. The main gaseous products of PC destruction in the plasma of an argon-oxygen mixture are H2, CO, and H2O molecules. In the first second after the discharge is turned on, H2 molecules are released at maximum rate and at a lower CO rate. The formation of carbon monoxide and hydrogen molecules occurs without the direct participation of oxygen under the action of active particles of argon plasma without the participation of active oxygen. Exposure to argon plasma leads to an increase in the oxygen content on the sample surface. In this case, the destruction of С – О, О–С(=О)–О bonds, which are part of the structure of the polycarbonate elementary unit, and the formation of new oxygen-containing bonds are observed. Etching of the polymer with active plasma particles leads to a change in the micro relief of the sample surface. A change in roughness and an increase in the concentration of polar functional groups increases the wettability of the PC film surface. A discussion of the possible mechanisms of the processes is made, which allows us to describe the observed results.