Surface modification of ultra-high strength polyethylene fibers for enhanced adhesion to epoxy resins using intense pulsed high-power ion beam

The effects of intense pulsed high power ion beam (HPIB) treatment of ultra -high strength polyethylene (UHSPE) fibers on the fiber/epoxy resin interfa ce strength were studied. For this study. argon ions were used to treat Spe ctra(TM) 1000 (UHSPE) fibers in vacuum. Chemical and topographical changes of the fiber surfaces were characterized using Fourier transform infrared s pectroscopy in attenuated total reflectance mode (FTIR-ATR), X-ray photoele ctron spectroscopy (XPS); dynamic wettability measurements, and scanning el ectron microscopy (SEM). The fiber/epoxy resin interfacial shear strength ( IFSS) was evaluated by the single fiber pull-out test. The FTIR-ATR and XPS data indicate that oxygen was incorporated onto the fiber surface as a res ult of the HPIB treatment. The wettability data indicate that the fibers be came more polar after HPIB treatment and also more wettable. Although the t otal surface energy increased only slightly after treatment, the dispersive component decreased significantly while the acid-base component increased by a similar amount. SEM photomicrographs revealed that the surface roughne ss of the fibers increased following the HPIB treatment. The single fiber p ull-out test results indicate that HPIB treatment significantly improved th e IFSS of UHSPE fibers with epoxy resin. This enhancement in IFSS is attrib uted to increased roughness of the fiber surface resulting in mechanical bo nding and in increased interface area, increased polar nature and wettabili ty, and an improvement in the acid-base component of the surface energy aft er the HPIB treatment.