ASTM D3849-07
(Test Method)Standard Test Method for Carbon Black-Morphological Characterization of Carbon Black Using Electron Microscopy
Standard Test Method for Carbon Black-Morphological Characterization of Carbon Black Using Electron Microscopy
SIGNIFICANCE AND USE
Carbon black morphology significantly affects the transient and end-use properties of carbon black loaded polymer systems. A carbon black’particle size distribution is its single most important property, and it relates to degree of blackness and rubber reinforcement. For a given loading of carbon black, blackness and reinforcement increase with smaller particle size. Aggregate size and shape (structure) also affect a carbon black’end-use performance, as higher carbon black structure increases viscosity and improves dispersion. The stiffness (modulus) of elastomer systems becomes significantly higher with increasing structure. The preferred method for measuring these properties is transmission electron microscopy.
Carbon black aggregate dimensional and shape properties are dependent upon the nature of the system in which the sample is dispersed, as well as the mixing procedure.
SCOPE
1.1 This test method covers the morphological characterization of carbon black primary aggregates from transmission electron microscope images. These measurements are used to derive the mean particle and aggregate size of carbon black in the dry (as manufactured) state, from CAB chip dispersion or removed from a rubber compound.
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.
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.
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Standards Content (Sample)
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Designation:D3849–07
Standard Test Method for
Carbon Black—Morphological Characterization of Carbon
1
Black Using Electron Microscopy
This standard is issued under the fixed designation D3849; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1.2 carbon black particle—a small spheroidally shaped,
paracrystalline,non-discretecomponentofanaggregate;itcan
1.1 Thistestmethodcoversthemorphologicalcharacteriza-
only be separated from the aggregate by fracturing. Carbon
tion of carbon black primary aggregates from transmission
black particle size is a distributional property; therefore, the
electron microscope images. These measurements are used to
term particle size implies the mean value from multiple
derive the mean particle and aggregate size of carbon black in
measurements.
the dry (as manufactured) state, from CAB chip dispersion or
3.1.1.3 glow discharge—a plasma of ionized gas that is
removed from a rubber compound.
formed in a high-voltage field at pressures of about 3 to 20 Pa
1.2 The values stated in SI units are to be regarded as the
-3
(25 to 150 3 10 torr). An alternating current (a-c) glow
standard. The values in parentheses are for information only.
discharge using air is effective in cleaning and oxidizing the
1.3 This standard does not purport to address all of the
surface of carbon substrates to improve the wetting character-
safety concerns, if any, associated with its use. It is the
istics of polar vehicles containing pigment dispersions.
responsibility of the user of this standard to establish appro-
3.1.1.4 substrate—a thin film that is used to support elec-
priate safety and health practices and determine the applica-
tron microscope specimens. Evaporated carbon films are com-
bility of regulatory limitations prior to use.
monly used because of relatively good mechanical strength,
2. Referenced Documents stability, and conductivity.
2
3.1.2 Aggregate Dimensional Properties from Image Analy-
2.1 ASTM Standards:
sis:
D6556 Test Method for Carbon Black—Total and External
3.1.2.1 area (A)—the two-dimensional projected area of the
Surface Area by Nitrogen Adsorption
carbon black aggregate image.
3. Terminology
3.1.2.2 perimeter (P)—the total boundary length of an
aggregate.
3.1 Definitions:
3.1.2.3 volume (V)—an estimate of the volume of the
3.1.1 General:
carbon black aggregate using stereological principles.
3.1.1.1 carbon black aggregate—a discrete, rigid colloidal
3.1.3 Image Analysis:
entity that is the smallest dispersible unit; it is composed of
3.1.3.1 dilation—the converse of erosion. This process is
extensively coalesced particles. Carbon black aggregate size is
accomplished by changing any OFF pixel to ON if it has
a distributional property; therefore, the term aggregate size
greater than a preset minimum of ON neighbors. This process
implies the mean value from multiple measurements.
causes image features to grow in size, which fills in small
breaks in features, internal voids, or small indentations along
1
This test method is under the jurisdiction ofASTM Committee D24 on Carbon the feature surface.
Black and is the direct responsibility of Subcommittee D24.81 on Carbon Black
3.1.3.2 erosion—the process by which image features are
Microscopy and Morphology.
reduced in size by selectively removing pixels from their
Current edition approved July 1, 2007. Published August 2007. Originally
periphery. It consists of examining each binary pixel and
approved in 1980. Last previous edition approved in 2004 as D3849–04. DOI:
10.1520/D3849-07.
changing it from ON to OFF if it has greater than a preset
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
minimum of neighbors that are OFF. It serves a number of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
useful functions, such as smoothing feature outlines and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. separating features touching each other.
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D3849–07
3.1.3.3 feature—areas within a single continuous boundary 5.8 Electrically Heated Tube Furnace, capable of being
that have gray-level ranges that allow them to be distinguished heated to 800 to 900°C under an inert environment, with the
from the background area outside the feature via thresholding. ability to introduce and remove the sample boat to the heated
3.1.3.4 thresholding—selecting a range of brightn
...
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