The use of γ -alumina-polymerized furfuryl alcohol resin binders in the fabrication of graphite

Two kinds of γ-alumina-polymerized furfuryl alcohol resins were synthesized and examined as graphite binder materials. Prior to their use, the resins were characterized according to viscosity and molecular size distribution. Investigation by gas chromatography showed that, relative to acid-polymerized resins, the γ-alumina-polymerized furfuryl alcohol resins contain large amounts of products that will not polymerize further. Extruded graphite rods were manufactured from both the γ-alumina-polymerized resins and from comparable acid-polymerized resins. The graphites fabricated with the γ-alumina-polymerized resins are shown to have generally poorer physical properties than those made with acid-polymerized resins of similar viscosities. Evidence is presented to show that not only must molecular size distribution be considered when evaluating the suitability of furfuryl alcohol resins as graphite binder materials, but also of importance is the capability of the low-molecular-weight resin components to further polymerize during heat-treatment.