A COMPARISON OF SOME INDIRECT METHODS OF MEASURING CARBON-BLACK DISPERSION IN RUBBER COMPOUNDS

An evaluation of the capability of four measurement methods of determi ning carbon black dispersion has been undertaken on compounds based on NR, EPDM, NBR and a blend of BR, NR and SBR. The Phillips dispersion rating (Dispergrader) was shown to be insensitive to changes in disper sion in the region explored and the dark field cut surface method (DFC S) is shown to measure only changes in macrodispersion. The results fr om both the microwave energy absorption method (Dielecmeter) and the e lectrical conductivity technique (Electroscanner) were shown to be res ponsive to changes in macro- and microdispersion.