Coupling of Epoxy Polymers to Graphite Fibers.

The information presented herein suggests that it is possible to induce carbonyl specificity to high modulus graphite fibers with subsequent coupling to the oxirane ring of epoxy matrices via a stannic chloride intermediate. Small quantities of a rayon precursor graphite fiber, approximately 100 mg, are treated in such a fashion and examined as to the bonding capability of fiber to epoxy matrix. The treatment proves successful in some areas tensile strength of the fibers is negligibly reduced and scanning electron photomicrographs of fractured tensile specimens indicate good resin-reinforcement adhesion. Although the treatment shows a potential for improving composite interlaminar shear strength, disadvantages lie in using highly toxic osmium tetroxide as a component in the wet chemical oxidation process, and presented difficulties involved in scaling the batch process to a continuous in-line operation. Based on high magnification scanning electron photomicrographs of as-received high modulus graphite fibers and treated fibers, a hypothesis for graphite fiber surface morphology is presented. Author-PL