New contributions of analytical ultracentrifugation to the investigation of dispersions

The particle size distribution of dispersions is an important parameter for viscosity, gloss and opacity and can be determined with great precision by analytical ultracentrifugation. A method using this technique has been developed at Bayer [1] and is now in widespread use. It was recently found to be the most satisfactory method in a recent ringtest of techniques for the submicron range. The high performance of this method is seen from the fact that a sample containing nine components can be analysed exactly. Its high resolving. power is proved by: a baseline separation of monodisperse components, differing by 10% of diameter only. To detect low quantities of small particles, measurements art performed at different concentrations and then coupled, yielding a high degree of precision. This method has been successfully applied to competitive growth experiments in emulsion polymerization and other areas.