Emulsion particle size II. determination of the distribution function using the ultracentrifuge

Abstract

The electron microscope has been the only instrument widely used in the determination of the particle size distribution of synthetic latices, although the use of an ordinary laboratory centrifuge has been investigated. In this report the use of a Spinco Model L ultracentrifuge in determining the particle size distributions of several acrylic latices is examined. It is shown that latices of poly ( n-butyl methacrylate) and poly ethyl acrylate give experimentally a log radius-normal probability distribution. However, latices of poly (methyl methacrylate) are shown to have their radii distributed normally in one case and log-normally in a second case. It is also shown that the electron microscope data of Ewart and Carr on polystyrene can fit both the distributions reasonably well. The data of French on poly (vinyl acetate), which are also electron microscope data, indicate that the particle radii are distributed log-normally.