Adhesion Improvement Between Armos Fiber And Thermoplastic Resins By Atmospheric DBD Plasma

As reinforcement materials, aramid fiber has many advantages, such as low density, high strength and modulus, thermal resistance and dimensional stability. However, the surface of aramid fiber is so smooth and chemically inert that the adhesion between fiber and the resin matrix is poor. This could do harm to the applications of aramid fiber reinforced resin composites. So it is necessary to modify the fiber. In this work, air atmospheric dielectric barrier discharge (DBD) plasma technology was used to modify fiber surface and then Armos fibers/PPESK composite was made.In this study, we investigated the effect of the treatment time with stable power density27.6W/cm3. chosen different times Os,9s,18s and27s. We also studied the effect of DBD plasma power density with stable treatment time18s, chosen different power densities OW/cm3,13.8W/cm3,27.6W/cm3and41.4W/cm3. The surface chemical composition, morphology and wettability were analyzed by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and dynamic contact angle analysis (DCAA), respectively; and single fiber tensile strength (SFTS) was measured. The interlaminar adhesion property was characterized by interlaminar shear strength (ILSS) measurement and scanning electron microscopy (SEM). The result showed DBD plasma treatment do change the surface chemical composition and morphology. After low power density and short time plasma treatment, the oxygen-containing polar groups were incorporated into Armos fiber surface; surface roughness of Armos fiber increased; the wettability between Armos and resin was enhanced. With these effects, the interfacial adhesion property of Armos fiber reinforced PPESK composite improved obviously, and the primary failure mode changed from interface failure to matrix failure. By contrast, the modification effect could decrease when Armos fiber was exposed to a violent DBD plasma.The result also showed that the optimal DBD plasma treatment was power density27.6W/cm3for18s. In this case, the contents of oxygen and nitrogen elements were18.1%.9.0%, respectively; the contact angle with water decreased to31.3°and the surface free energy increased to68.3mJm2. However. SFTS of Armos fiber only decreased1.9%, which can be neglected. The ILSS of Armos fiber/PPESK composite was71.4MPa, increased by17.2%. and the failure mode was matrix failure.