Scope:

The greater a carbon black resists compression by having substantial aggregate irregularity and non-sphericity, the greater the compressed and void volumes. So for the sake of more carbon black compression, a high amount of energy is required to compress the sample per unit void volume.

Procedure:

In ASTM D7854, the measured compressed volume of a weighed dry test sample is obtained in a void volume instrument. The instrument consists of an apparatus capable of applying a uniaxial compression to a test sample in a cylindrical sample chamber, and the transmitted forces are measured. The compressed void volume is obtained by subtracting the theoretical volume from the apparent volume; then results are recorded.

Video 01: Carbon black dispersion tester

Specimen details:

The depth of carbon black should be 10 mm for ASTM D7854.

Result:

The void volume of carbon black per unit is calculated as follows:.

                       VV = (V_A – V_T) / m (100)

In this way, by performing the ASTM D7854 test, the carbon black-void volume can be measured at a mean pressure.

Conclusion:

ASTM D7854 covers a procedure to determine a carbon black structure property known as void volume at mean pressure.