Investigations on the cross-linking of the binder pitch matrix of carbon bodies with molecular oxygen — Part II. Kinetics and effects of cross-linking of the binder pitch matrix on the properties of the carbon bodies Original Research Article

A green mix composed of 65% pitch coke powder and 35% petroleum pitch (Ashland A 240) was shaped into cylindrical bodies, 30 mm in diameter and 30 mm in height. The bodies were treated with flowing pure oxygen at 200 °C and pressures of 0.1 MPa and 1 MPa. The kinetics of oxidation were analyzed by measuring the oxygen uptake, radial temperature gradients in the body, formations of CO2 and CO and by determination of radial oxygen profiles. Properties of the bodies were determined after carbonization at 1000 °C and graphitization treatment at 2450 °C. Severe pore diffusion problems were found not to exist. This result is explained by a strong temperature selectivity of the oxidation reactions. At a given temperature, the reactions are limited to the oxidation of special groups, which allows the reaction front to move from the surface into the core of the body without remarkable over-oxidation of the skin. By an optimum oxygen treatment the flexural strength after graphitization treatment of the bodies is increased from about 10 to about 40 MPa.