Effects of plasma-induced epoxy coatings on surface properties of Twaron fibers and improved adhesion with PPESK resins

•Epoxy resin was coated after plasma pretreatment to improve the interfacial adhesion of composite.•The coatings were chemically bonded and physically absorbed onto the fiber surface.•The ILSS increased with a 68.9% increment after coating.•The diffusion and entanglement of the molecules enhanced the interfacial adhesion.

This work deals with the oxygen and argon plasma-induced coating process on the surface of Twaron fibers to obtain a strong interfacial adhesion between the fibers and PPESK matrices. The epoxy coating resins applied in this study were chemically bonded with the plasma pretreated fibers, which was confirmed by X-ray photoelectron spectroscopy (XPS). The fiber surface morphologies and wettability were analyzed by scanning electron microscope (SEM) and dynamic contact angle analysis, respectively. The interfacial adhesion performance of the Twaron fiber-reinforced PPESK composite was measured by interlaminar shear strength (ILSS) and water absorption tests. The fracture mechanisms of composites were examined by SEM. The results indicated that after coating the surface wettability was improved and the ILSS had an increment of 66.1% for oxygen-plasma-induced coating and 68.9% for argon-plasma-induced coating.