THE INFLUENCE OF MONOMER AND POLYMER PROPERTIES ON THE REMOVAL OF ORGANIC VEHICLE FROM CERAMIC AND METAL MOLDINGS

This paper describes the effects of monomer and polymer properties on the competition between degradation of organic vehicle and transport o f degradation products in ceramic moldings during pyrolysis. An experi mentally tested model is studied systematically for ranges of material and process parameters characteristic of known polymers and their deg radation products. The work highlights the properties having the great est influence on the successful removal of organic vehicle from molded ceramics. The polymer properties controlling the diffusion constant a re linked to the temperature dependence of viscosity of the molten sus pension. Enthalpy of vaporization of the organic vehicle and the activ ation energy for the diffusion coefficient have a commanding influence on the critical heating rate for avoidance of defects. Preliminary gu idelines emerge for the design of polymers for plastic forming of cera mic suspensions.