ASTM D7854-13

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Designation: D7854 − 13
StandardTest Method for
Carbon Black-Void Volume at Mean Pressure
This standard is issued under the fixed designation D7854; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 Definitions of Terms Specific to This Standard:
3.2.1 applied pressure, n—the pressure exerted on a sample
1.1 Thistestmethodcoversaproceduretomeasureacarbon
mass by a movable piston in a cylindrical chamber, where the
black structure property known as Void Volume at mean
load cell or force measuring system is in contact with the
pressure. Compressed void volumes are obtained by measuring
movable piston.
the compressed volume of a weighed sample in a cylindrical
chamber as a function of pressure exerted by a movable piston.
3.2.2 compressed volume (carbon black), n—the apparent
A profile of void volume as a function of pressure provides a
volume that a specified mass of carbon black occupies when it
means to assess carbon black structure at varying levels of
is contained in a specified cylindrical chamber and subjected to
density and aggregate reduction.
a single uniaxial compression at a specified pressure by means
of a movable piston.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
3.2.3 geometric mean pressure, n—the geometric mean of
standard.
the applied and transmitted pressures at a specific void volume;
the geometric mean pressure is defined in Eq 1:
1.3 This standard does not purport to address all of the
0.5
safety concerns, if any, associated with its use. It is the
Geometric Mean P 5 P 3 P (1)
~ !
GM a t
responsibility of the user of this standard to establish appro-
3.2.4 theoretical volume (carbon black), n—the volume that
priate safety and health practices and determine the applica-
a specific mass of carbon black would occupy if there were no
bility of regulatory limitations prior to use.
void space within the carbon black, and is given by the ratio of
mass to skeletal density, where the skeletal density is deter-
2. Referenced Documents
2 mined by an accepted test method.
2.1 ASTM Standards:
3.2.5 transmitted pressure, n—the resulting pressure trans-
D1799 Practice for Carbon Black—Sampling Packaged
mitted through a sample in a cylindrical chamber, where the
Shipments
load cell or force measuring system is in contact with the
D1900 Practice for Carbon Black—Sampling Bulk Ship-
sample opposite the movable piston, typically via a stationary
ments
second piston.
D2414 Test Method for Carbon Black—Oil Absorption
Number (OAN)
3.2.6 void volume (carbon black), n—a measure of the
D3493 Test Method for Carbon Black—Oil Absorption
intra-aggregate void space or occluded volume within the
Number of Compressed Sample (COAN)
primary structure of carbon black, characterized by the irregu-
D4821 Guide for Carbon Black—Validation of Test Method
larity and non-sphericity of carbon black aggregate particles,
Precision and Bias
and expressed as the difference (compressed volume minus
D6086 Test Method for Carbon Black—Void Volume (VV)
theoretical volume) as a function of specified uniaxial com-
pression pressure, and normalized to 100 g mass.
3. Terminology
3.2.6.1 Discussion—Carbon blacks resist packing,
3.1 Refer to Sections 4 and 9 for a more complete under-
compression, and fracture due to aggregate irregularities and
standing of the use of these terms in this test method.
entanglements, size distribution, and aggregate strength result-
ing from particle to-particle necks within aggregate branches.
This test method is under the jurisdiction ofASTM Committee D24 on Carbon
Compressed void volume is also affected by reacting forces to
Black and is the direct responsibility of Subcommittee D24.11 on Carbon Black
the cylinder wall and the piston tip, which in turn depend on
Structure.
factors including sample shape (that is, the ratio of sample
Current edition approved Nov. 1, 2013. Published December 2013. DOI:
10.1520/D7854-13.
height to cylinder diameter) or interfacial area, which can
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
influence the uniformity of the compaction density. Since
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
compressed void volumes as a function of applied pressure are
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. known to be specific to sample mass and cylinder geometry,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7854 − 13
such a compressed void volume is biased due to error in the function of applied pressure, from which the void volume is
applied pressure relationship. The applied pressure bias is a calculated at specified intervals of geometric mean pressure
result of force losses due to friction between the sample and (that is, geometric mean of applied and transmitted pressures).
cylinder wall interface. There is presently no known technique The void volume instrument or device shall conform to the
to properly correct applied pressure measurements for an following generic specifications and be capable of operating as
instrument design using a single load cell since friction outlined in Section 9.
coefficients (µ) are not constant for carbon black products or 6.4.1 The instrument shall have a rigid framework that
applied pressures. For this reason, the most useful technique contains a cylindrical sample chamber. Hysteresis and elastic-
for comparing compressed void volumes is based on a numeri- ity in the framework under the range of applied forces should
cal technique known as mean compaction force or mean be accounted for in the displacement measurement.
pressure. The mean pressure technique requires an instrument
6.4.2 The cylinder shall have a uniform diameter.
design consisting of two load cells to enable the measurement 6.4.3 By means of a suitable mechanism with sufficient
of compressed void volume as a function of applied and
power for the compression forces as required for testing, the
transmitted force or pressure. Such a design allows the com- pistonshallbecapableofbeingmovedtocompressthesample.
putation of void volumes at mean pressures, a method which
A device to record the movement of the piston and measure
has been demonstrated to minimize the effects of carbon black
displacement shall be provided. The compressed volume of
sample mass and cylinder geometry.
any sample is determined by the distance from the end of the
pistontotheendofthecylinder;thisisdesignatedasa“height”
4. Summary of Test Method
in the calculations discussed in Section 10. The sample height
and cylinder diameter are used to calculate an apparent sample
4.1 The measured compressed volume (apparent volume) of
volume.
a weighed dr
...