Effects of a pulsed XeCl excimer laser on ultra-high strength polyethylene fiber and its interface with epoxy resin

The effects of excimer laser treatment on the changes in the surface topography, the physical and chemical properties of ultra-high strength polyethylene (UHSPE) fibers; and their interfacial property with epoxy resin were investigated. The scanning electron microscopy (SEM) photomicrographs show that UHSPE fibers exhibit a rougher surface after irradiation with the XeCl pulsed excimer laser as a result of intense laser heat and ablation. The wettability and surface chemistry of control and laser-treated UHSPE fibers were monitored by TRI wettability/friction apparatus. The chemical changes on the surfaces of UHSPE fibers were analyzed by Fourier transform infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode. The tensile properties of single fibers, before and after laser treatment, were studied using an Instron tensile tester. Interfacial shear strength (IFSS) measurements were performed using the single-fiber pull-out test. The fiber surface becomes polar after the laser treatment with increased acid-base contribution. The strength of laser-treated UHSPE fibers is lower than that of the control fibers. The IFSS results indicate that laser treatment improves the adhesion strength of UHSPE fibers with epoxy resin because of the changes in surface chemistry and enhanced roughness. The results show the potential of the excimer laser as an alternative surface treatment for fibers to enhance their adhesion with epoxy resins.