The Effect of Atmospheric-Pressure Air Plasma Discharge Power on Adhesive Properties of Aramid Fibers

After exposure to the atmospheric-pressure air plasma at different discharge powers, the adhesion characteristics of Twaron aramid fibers were investigated. For the 12 s-300 W plasma treatment, the interlaminar shear strength of Twaron fiber reinforced thermoplastic poly(phthalazinone ether sulfone ketone) was increased from 46.0 to 61.7 MPa by 34.1%, and the diffusion of water molecule into the resulting composites was proved to be effectively prevented. These results showed that surface adhesive properties of the plasma-treated aramid fibers were improved. At the power level of 300 W, X-ray photoelectron spectroscopy analysis revealed the increases in concentrations of oxygen and nitrogen polar groups on the fiber surface, and atomic force microscopy observations led to the conclusion that the fiber surface morphology was changed and the surface roughness was greatly increased. These new polar and irregular surface structures accounted for the better adhesion between the fiber and the matrix, while due to the reasonability of this discharge power level applied to the surface modification, the measured fiber tensile strength only decreased by 2.0%. (C) 2014 Society of Plastics Engineers