Characterization of S-glass/polysulfone adhesive failure using ion scattering spectroscopy and secondary ion mass spectrometry

Abstract The fracture surfaces of S-glass/polysulfone adhesive bond failures were examined using ion scattering spectroscopy (ISS) and secondary ion mass spectrometry (SIMS). When polysulfone was bonded directly to a clean S-glass surface, it was found that shear failure occurred at about 12.1 × 10 6 N/m 2 by cleavage of the polysulfone within 30 A of the glass surface. High concentrations of alkali metals and flourine were found in the surface layers adjacent to the fracture surface to a depth of about 100 A into the polysulfone phase. When the S-glass surface was coated with a γ-aminopropyltriethoxysilane coupling agent, the shear failure occurred at about 21.5 × 10 6 N/m 2 by cleavage of the polysulfone within 20 A of the silane/polysulfone interface. Once again high concentrations of alkali metals and fluorine were found in the surface layers adjacent to the fracture surfaces. It appears that the compatability of the polymer melt with the bonding surface and the level of impurities at that surface control the bond strength of the adhesive joint. This may be explained on the basis that the surface energy γ sv of the silane-coated S-glass is higher than the surface free energy γ sv of the uncoated S-glass and that it approaches the surface free energy of the liquid adhesive in the melt, lowering the surface free energy γ sl at the solidliquid interface.