Effect of fuming nitric acid surface treatment of ultra‐high modulus polyethylene fibers on the mechanical properties of their composites

Abstract The effect of hot fuming nitric acid (FNA) treatment on the adhesion of ultra‐high modulus polyethylene fabrics to an epoxy resin has been investigated. Mechanical and molecular characterization of the interface has been attempted. Fourier transform infrared diffuse transmittance spectroscopy has been used to monitor the chemical changes introduced by the FNA treatment as well as the nature of the interface between the fibers and the epoxy resin on the molecular level. Scanning electron microscopy has been used to examine the morphological consequences of the FNA treatment. Flexural and interlaminar shear properties of the composites have been measured as a function of the extent of surface treatment. Esterification of the FNA treated polyethylene fibers is used to examine the role of surface functionality to the mechanical performance.