ASTM D6556-01
(Test Method)Standard Test Method for Carbon Black—Total and External Surface Area by Nitrogen Adsorption
Standard Test Method for Carbon Black—Total and External Surface Area by Nitrogen Adsorption
SCOPE
1.1 This test method covers the determination of the total surface area by the Brunauer, Emmett, and Teller (B.E.T. NSA) theory of multilayer gas adsorption behavior using multipoint determinations and the external surface area based on the statistical thickness surface area method.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (The minimum safety equipment should include protective gloves, sturdy eye and face protection).
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Designation: D 6556 – 01
Standard Test Method for
Carbon Black—Total and External Surface Area by Nitrogen
1
Adsorption
This standard is issued under the fixed designation D 6556; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope nitrogen adsorption. The NSA measurement is based on the
B.E.T. theory and it includes the total surface area, inclusive of
1.1 This test method covers the determination of the total
micropores, pore diameters less than 2 nm (20 Å). The external
surface area by the Brunauer, Emmett, and Teller (B.E.T. NSA)
surface area, based on the statistical thickness method (STSA),
theory of multilayer gas adsorption behavior using multipoint
is defined as the specific surface area that is accessible to
determinations and the external surface area based on the
rubber.
statistical thickness surface area method.
1.2 The values stated in SI units are to be regarded as the
5. Apparatus
standard. The values given in parentheses are for information
5.1 Multipoint Static-Volumetric Gas Adsorption Apparatus,
only.
with Dewar flasks and all other accessories required for
1.3 This standard does not purport to address all of the
operation.
safety concerns, if any, associated with its use. It is the
5.2 Sample Cells that, when attached to the adsorption
responsibility of the user of this standard to establish appro-
apparatus, will maintain isolation of the sample from the
priate safety and health practices and determine the applica-
–5 3
atmosphere equivalent to a helium leak rate of <10 cm /min,
bility of regulatory limitations prior to use. (The minimum
per atmosphere of pressure difference.
safety equipment should include protective gloves, sturdy eye
5.3 Balance, Analytical, with 0.1 mg sensitivity.
and face protection).
5.4 Heating Mantle or Equivalent, capable of maintaining a
2. Referenced Documents temperature of 300 6 10°C.
5.5 Oven, Gravity Convection, capable of maintaining a
2.1 ASTM Standards:
temperature of 125 6 10°C.
D 1799 Practice for Carbon Black—Sampling Packaged
2
Shipments
6. Reagents
D 1900 Practice for Carbon Black—Sampling Bulk Ship-
2 6.1 Liquid nitrogen, 98 % or higher purity.
ments
6.2 Ultra-high purity nitrogen gas, cylinder or other source
D 3324 Practice for Carbon Black—Improving Test Repro-
2 of prepurified nitrogen gas.
ducibility Using ASTM Reference Blacks
6.3 Ultra-high purity helium gas, cylinder or other source of
D 4483 Practice for Determining Precision for Test Method
2 prepurified helium gas.
Standards in the Rubber and Carbon Black Industries
7. Sampling
3. Summary of Test Method
7.1 Samples may be taken in accordance with Practice
3.1 The total and external surface areas are measured by
D 1799 and Practice D 1900.
evaluating the amount of nitrogen adsorbed, at liquid nitrogen
temperature, by a carbon black at several partial pressures of
8. Sample Preparation Procedure
nitrogen. The adsorption data is used to calculate the NSA and
8.1 Dry a portion of carbon black at 125°C for 1 h. If the
STSA values.
carbon black is known to be substantially free of moisture, or
4. Significance and Use subsequent preparation steps are known to be adequate for
moisture removal, then this step may be omitted.
4.1 This test method is used to measure the total and
8.2 Condition an empty sample cell for a minimum of 10
external surface area of carbon blacks based on multipoint
minutes at the same conditions intended for degassing the
sample. Weigh the empty sample cell to the nearest 0.1 mg and
1
This test method is under the jurisdiction of ASTM Committee D24 on Carbon
record the mass.
Black and is the direct responsibility of Subcommittee D24.21 on Adsorptive
8.3 Weigh approximately 0.4 g of the carbon black into the
Properties of Carbon Black.
sample cell.
Current edition approved May 10, 2001. Published July 2001. Originally
published as D 6556-00. Last previous edition D 6556-00a.
NOTE 1—For carbon black powder samples, add enough carbon black
2
Annual Book of ASTM Standards, Vol 09.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
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D 6556
to give a depth of approximately 2 in. in straight wall sample tubes, or
the 0.1 to 0.5 relative pressure (P/P ) range. For some tread
o
approximately 0.4 g for bulb-type sample cells.
carbon blacks, particularly N100 and N200 series, it is neces-
sary to measure two additional data points, 0.05 and 0.075, in
8.4 Flow Degassing:
order to increase the accuracy of the NSA measurement. A data
8.4.1 Open the gas control valve and
...
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