Physics : Particle Shape Distribution

986 Words Dec 7th, 2015 4 Pages
3.2.3. Particle shape distribution
Particle shape is the recognised pattern of relationships among all of the points forming the external particle surface (Luerkens et al., 1987). Particle shape is one of the most uncontrollable factors in powder technology. Different production techniques (e.g. nonsolvent precipitation, spray drying, freeze-drying, etc.) for one material will practically continuously lead to the production of particles of different shapes, and even particles that have experienced similar treatments may exhibit different shapes. Most pharmaceutical solid particles are diverged from the spherical shape (Hickey and Concessio, 1997). Nevertheless, all equations that compute the interparticle forces (either van der Waals, capillary or electrostatic forces) are built on the unrealistic situation, which assumes that particles of a predetermined shape interact under theoretical conditions (i.e., an interaction between perfect spheres with perfectly smoothed surfaces). Therefore, any effort to deduce an equation that accurately calculates the interparticle forces between the real irregular-shaped particles would prove to be unrealistic. Nevertheless, a qualitative assessment of the particulate interaction within a powdered system is possible using the simple principles generated from perfect situations.
Particle shape could have a significant effect on powder charge (Murtomaa et al., 2004a). (Chakrabarty et al., 2008) argued that the possibility of a particle…

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