In the ASTM D 3849 task force it was shown, that a general conversion from STSA into a mean particle size diameter (MPS) might work for ASTM grades only. However, for specialty grades, especially designed and produced for the pigment market the conversion is not applicable. Examples have been shown where the MPS remained constant, but the STSA tremendously changed. Also carbon blacks with a special designed aggregate size distribution (ASD) can create smaller MPS values at comparable STSA data. The current conversion table included in the current D 3849 standard does not include specialty application blacks in an adequate way. Therefore the table should be revised.
Keywordsaggregate size; automated image analysis; carbon black; electron microscopy; particle size; statistical thickness surface area;
Draft Under Development