CHARACTERIZATION OF THE SURFACE AND INTERPHASE OF PLASMA-TREATED HM CARBON-FIBERS

The surface chemistry and morphology of HM carbon fibres, treated with pulse-voltage excited air, oxygen, nitrogen and acrylonitrile plasmas , are characterized by high-resolution X-ray photoelectron spectroscop y and transmission electron microscopy. Oxygen- and nitrogen-containin g species are generated on the surface under plasma treatment without significant changes in the fibre morphology. Comparable interfacial sh ear strengths are found for single-fibre model composites prepared wit h amine-cured epoxy resin, with a highest value of 61.4 MPa for air-pl asma-treated fibres. The surface chemistry of the fibres if found to i nfluence the degree of epoxy consumption at the earlier stages of the cure process, as determined by Fourier transform infra-red microscopy and differential scanning calorimetry. (C) 1997 Elsevier Science Limit ed.