Jan Peska

The influence of porosity of discrete particles upon their apparent dimensions as measured by the Coulter principle

Abstract Highly porous particles furnish, due to their porosity, smaller Coulter diameters and Coulter volumes than the real particle size and envelope volume, respectively. Finding a relation between these variables (eqn. 4) makes the determination of the latter easier. In addition to the readily obtainable Coulter and porosity data, only one empirical constant for each material class has to be determined.

Surface oriented mercuration of poly(vinylaromatics)

Abstract The mercuration of styrene-divinylbenzene co-polymers can be directed either into the bulk or to the surface of the particles by choosing the reaction medium. Taking macroreticular co-polymers, e.g. Amberlite XAD 2 or XAD 4, the substitution can be limited to a narrow layer of the inner surface of the material, resulting in a rapid ion exchange with extremely high selectivity towards chloride ions.