Statistical model for the random packing of real power particles

A statistical model for the packing of irregularly shaped powder particles has been developed. It has been based on experimental measurements for the packing of specially synthesized particle size distributions of poly(vinylidene chloride) powder. It is shown that, as the coefficient of variation (ratio of standard deviation/mean particle size) decreases, so does the fraction of theoretical density. It is also shown that for real powders the packing density is very low, with predicted values being only about one third of the values obtained in idealized random packing of spherical particles. The difference is attributed to the irregular shape of real particles and additional factors such as friction, adhesion and surface forces which are very sensitive to particle size.