| abstract |
A process is described for producing spherical microarticles based on cellulose acetate with particle sizes in the range from 0.1 to 100 μm and adjustable porosity in the range from 5 to 95%, which e.g. can be used advantageously as separating and carrier materials for chromatographic and diagnostic purposes in the fields of biotechnology, biochemistry and medicine. Here, cellulose acetate is dissolved in a halogen-hydrocarbon-free solvent mixture consisting of two or more components, which individually do not represent a solvent for the cellulose acetate in question, are volatile at temperatures below 100 ° C. and at least one component of which is immiscible or only miscible with water. This polymer solution is dispersed in an aqueous medium which optionally contains a water-soluble salt and / or at least one of the organic solvent components used to dissolve the cellulose acetate to adjust the porosity. The resulting polymer droplets are coagulated by evaporation of the solvents, separated from the dispersion medium and washed, it being possible for the resulting cellulose acetate microspheres to be partially or completely saponified in the dispersion medium or after isolation and purification. |