XPS analysis of the coverage and composition of coatings on glass fibres

For a fundamental approach to glass fibres for composite applications, it i s essential to develop efficient methods to analyse the composition and dis tribution of the sizing layer on the glass filaments, We have been investig ating the use of X-ray photoelectron spectroscopy (XPS) as a tool for the r apid characterization of the sizing and interphase in glass fibre reinforce ments. In this report we present and discuss a model, based on a patchy siz ings overlayer hypothesis, to assist the data reduction of XPS spectra from glass fibres coated with organic sizings. We show how plots of atomic rati os can be used to estimate the surface coverage of the sizing on glass fibr es and to obtain information on the stoichiometry of the sizing. The result s generated using this model are in good agreement with previously publishe d data. Using this model, we show that XPS results combined with the weight fraction of the sizing give a quantitative value for the coverage of the f ibre surface by the sizing.