Physics of Tablet Compression XV. Thermodynamic and Kinetic Aspects of Adhesion Under Pressure

Abstract

A theoretical analysis has been made of the processes by which interparticle adhesion can occur during the compression of tablet granulations in the absence of added fluid adhesives. A reasonable explanation for the development of adhesion in these systems is based on the occurrence of either partial fusion or partial dissolution at the surfaces of the particles induced by energy added during the compression. The possibility that these phenomena do occur gains partial support from an examination of the thermodynamics and kinetics of surface processes that may take place. The Clapeyron equation cannot be applied directly to these processes, but must be modified to take into account the nonuniformity of the pressures exerted on the particles during compression. Another factor which may affect particle adhesion is the production of highly localized frictional heat and slow diffusion of this heat from the particle surfaces into their interior.