Nanomaterials as Flow Regulators in Dry Powders

Abstract

Abstract From a physical point of view powders represent an intermediary state between solids and fluids. This holds especially with respect to their flow properties. Gravitational forces as well as interparticle forces are acting on particles in bulk powders. As long as the gravitational forces are prevailing the powder is able to flow. However as soon as the interparticle forces dominate the powder becomes cohesive. It does not flow any longer. Based on empirical observations highly dispersed Silicone dioxide is added to powders to improve their flowability. In the present paper we will present some findings obtained from studies on binary mixtures consisting of 0.2(m/m) of a nanoscaled material and corn starch. They give some insight into the mechanism of action of flow regulators. In addition they allow to classify flow regulators with respect to their efficiency as well as to their effectiveness. Furthermore the findings give hints on how to optimize existing flow regulators or to develop new improved ones.