Abstract
Influence of particle size of boric acid, aspirin or magnesium alumino silicate on fluidity and packing property of the binary mixtures of starch was investigated. For the mixtures of starch and boric acid or aspirin, angle of repose decreases gradually with the increase of proportion of boric acid or aspirin above critical size, while minimum angle is obtained for the mixture containing a certain proportion of smaller particles. It is suggested that cohesion of starch particles is scarcely influenced by adhesion of starch to particles above critical size, and that it decreases by the adhesion to them below critical size. Porosity of the mixture is a little larger than the arithmetic mean value of porosity of starch and boric acid or aspirin. Remarkably small values of angle of repose and porosity are obtained for the mixture of starch and magnesium alumino silicate. Magnesium alumino silicate particle is suggested to take moisture away from starch particle.
