Rapid Surface Treatment of Polytetrafluoroethylene using Ar - Atmospheric Pressure Microwave Plasma

Abstract

Surface treatment of polytetrafluoroethylene (PTFE) for the refinement of adhesion strength using Ar - atmospheric pressure microwave (2.45 GHz) after glow plasma system was examined to realize high speed treatment. The sample film (65 mm × 50 mm × 0.5 mm) was wrapped around a rotating dram (20 mmφ, 6 rpm) which was set at right angles to the discharge tube just under the wave guide and irradiated by the hot plasma flow. Gas steady temperature of the irradiated surface reached about 480 ℃ at 829 W of the discharge power. After short time irradiation, the film was bonded with stainless steel plate by an epoxy glue. At 42 sec plasma irradiations to the surface, we obtained 2.2 kNm^-1 as the highest peel strength measured by 180° peel test. This value is much higher than the cohesive failure of PTFE verified by XPS measurement. We succeeded much faster treatment than that of the normal heat-assisted He atmospheric pressure glow discharge, using with the microwave plasma system without of any heating system.