OXYGEN CONCENTRATION ON SURFACES OF CARBON-FIBERS

The performance of carbon fiber reinforced composites depends significantly on the interface between the fiber surfaces and the resin matrix. Good adhesion is a precondition for the intended transfer of stresses in the fiber polymer composites. For carbon fibers, the oxidized surface treatment is a widely accepted method to achieve good adhesion. In the present study, five pitch/polyacrylonitrile based carbon fibers were surface treated with various chemical agents, such as nitric acid, peroxide, oxygen, and acid/hydrogen. The oxidized surfaces were characterized by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and Auger spectroscopy for surface morphology, carbon—oxygen functional groups and oxygen distributions. In particular, scanning Auger microanalysis was extensively employed for the detailed determinations of oxygen distributions on the fiber surfaces. These results indicate that the formation of oxides on the fiber surfaces varies widely from region to region, segment to segment, and strand to strand. The available amounts of surface oxides are dependent on the fiber structure as well as the precursors. © 1990, American Vacuum Society. All rights reserved.