HIGHLY FILLED PARTICULATE THERMOPLASTIC COMPOSITES .1. PACKING DENSITY OF IRREGULARLY SHAPED PARTICLES

The packing density of irregular shaped particles greatly affects the properties of highly filled particulate composite materials. The effec ts of particle size distribution parameters on the packing density of fused silica powder and cristobalite flour powder of different size ra nges is reported. Various size distributions, according to the log-nor mal function, were prepared by sieving and characterized by light scat tering, using a Malvern 2600 light scattering instrument. The apparent and tap density of the various powders was used to characterize the p acking density. The size distribution width was found to have a major effect on the packing density. In addition, the particle size was foun d to affect the packing density however, its significance depends on t he size range and shape of the particles. Mixtures of powders, each ha ving a different size distribution, behave differently.