HIGH-QUALITY AND HIGHLY ORIENTED GRAPHITE BLOCK FROM POLYCONDENSATION POLYMER-FILMS

High-quality and highly oriented graphite was produced in the form of a thick block having physical properties close to those of single-crystal graphite. It was prepared from polyimide films of 25 mu-m thick with high molecular orientation. A sheaf of the films was heat treated in an argon atmosphere at temperatures up to 1000-degrees-C (carbonization) and then heated for graphitization up to 3000-degrees-C under a pressure between 100 and 300 kg/cm2. Graphite blocks as large as 150 x 50 x 13 mm3 were prepared, and the mosaic spread (the degree of preferred orientation) attained was 0.4-degrees.