Effect of temperature changes on the densification and compression of griseofulvin and sucrose powders

A study has been made of the effect of varying the temperature between - degree and -25 degree C on the densification and low pressure compression of griseofulvin, sucrose and mixtures of the two powders. Densification and compression of the materials were facilitated as they were cooled in the range of homologous temperatures (ratio of the experimental temperature in degree K to melting point of the material in degree K) from 0.7 to 0.5. This was attributed to a reduction in the cohesive forces operating between the particles. Values are given for the activation energies of densification and compression derived by plotting the logarithms of these properties versus the reciprocal of the absolute temperature. For both materials and their mixtures the activation energies were in the range of about 1 to 10kJ mol-1 showing that physical rather than chemical forces were operating between the particles.