ASTM D7723 Macro-Dispersion of Fillers in Compounds

Scope:

In this ASTM D7723 test method, filler macrodispersion, as a measure of mixing quality, is used to characterize their assimilation into the rubber matrix. This also tests the ability of colored rubbers to mix well. To photograph a broad spectrum of colors, it uses variable exposure.

Procedure:

In ASTM D7723, the already cut specimen is placed in front of the testing window within two minutes of cutting the specimen. Then, a minimum of three scans of different body parts are done. It is necessary to take a newly cut surface. For the five scans, a new cut is made. Towards the end of the procedure, calculations are carried out.

Video 01: Determination of rubber properties by stress relaxation test systems

Specimen size:

The thickness of the uncut specimen must be at least 5 to 10 mm.

Data:

The following formula is used in ASTM D7723 to determine the dispersion percentage:

Dispersion % = 100 – 100 URF%/L 

URF% is the % of total scan of undispersed filler measured in reflection
L is the filler volume fraction in the compound.

Conclusion:

In this ASTM D7723 test method, filler macrodispersion, as a measure of mixing quality, is used to characterize their assimilation into the rubber matrix.