ASTM D4218-96(2001)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D4218–96 (Reapproved 2001)
Standard Test Method for
Determination of Carbon Black Content in Polyethylene
Compounds By the Muffle-Furnace Technique
This standard is issued under the fixed designation D 4218; 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 3.2 Definitions of Terms Specific to This Standard:
3.2.1 channel black—those carbon blacks produced by a
1.1 This test method covers the determination of black
process that operates in an open system in which a multitude of
polyethylene compounds containing channel or furnace black.
small diffusion flames burn in air and carbon is deposited on
It is not applicable to thermal black.
cooled surfaces.
1.2 This test method is not suitable for plastics that char on
3.2.2 furnace black—those carbon blacks produced using
pyrolysis and should not be attempted for plastics that generate
the principle of continuous oxidative combustion in closed
corrosive fumes on pyrolysis.
systems.
1.3 The values stated in SI units are to be regarded as the
3.2.3 thermal black—those carbon blacks based on a pro-
standard.
cess that uses thermal decomposition in the absence of oxygen
1.4 This standard does not purport to address all of the
andoperatesinaclosedsystem.Particlesgrowveryslowlyand
safety concerns, if any, associated with its use. It is the
can become very large and filamentous structures.
responsibility of the user of this standard to establish appro-
3.3 Symbols:Symbols—Units and symbols used in this test
priate safety and health practices and determine the applica-
method are those recommended in Practice E 380.
bility of regulatory limitations prior to use. Specific hazard
statements are given in Section 7.
4. Summary of Test Method
NOTE 1—There is no similar or equivalent ISO standard.
4.1 Black polyethylene compound contained in a disposable
aluminum weighing dish is pyrolyzed in a muffle furnace for a
2. Referenced Documents
short period. During the pyrolysis of the polymer, the air in the
2.1 ASTM Standards:
muffle furnace becomes oxygen-deficient to prevent the com-
D 883 Terminology Relating to Plastics
bustion of the residual carbon black. Any soot, as defined in
D 1603 Test Method for Carbon Black in Olefin Plastics
Test Method D 2741, produced by the initial combustion of the
D 2741 Test Method for Susceptibility of Polyethylene
gases is consumed before the carbon black itself.
Bottles to Soot Accumulation
4.2 After cooling and weighing for residual carbon black,
E 380 Practice for Use of the International System of Units
the dish and contents may be reinserted into the muffle furnace
(SI) (The Modernized Metric System)
to determine ash content and the results used to determine true
E 691 Practice for Conducting an Interlaboratory Study to
carbon black content. This should be done only if the com-
Determine the Precision of a Test Method
pound is suspected of containing mineral fillers as well as
carbon black.
3. Terminology
3.1 Definitions: For definitions of plastics terms used in this
5. Significance and Use
test method, see Terminology D 883.
5.1 This test method is capable of yielding duplicate test
data, in 20 min or less, for a simple carbon black content
determination.
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods 5.2 This test method is suitable for manufacturing quality
(Section D20.70.01).
control, technical service, and research work.
Current edition approved July 10, 1996. Published September 1996. Originally
published as D 4218 – 82. Last previous edition D 4218 – 91.
This revision includes the addition of an ISO equivalence statement and an
expanded terminology section.
Annual Book of ASTM Standards, Vol 08.01
Annual Book of ASTM Standards, Vol 08.02.
Discontinued; see 1997 Annual Book of ASTM Standards, Vol 14.04.
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4218
5.3 For referee requirements, the number of replicate mea- 10.2 Set the controller indicator to 600°C and let it stabilize
surements is increased. Alternatively, a control sample of from 600 to 610°C.
known carbon black content is tested with the unknown 10.3 Mark an aluminum weighing dish with an identifying
sample. impression on the tab.
5.4 Test Method D 1603 is available for referee testing 10.4 Place the dish on the screen in the muffle furnace and
should the involved parties so desire. burn off the surface oil for 2 min, as indicated by timer.
10.5 Transfer the dish to the desiccator and let it cool for at
6. Apparatus
least 2 min.
10.6 Weigh the dish accurately on the analytical balance.
6.1 Fume Hood or Vent Hood.
Record the results as W .
6.2 Muffle Furnace, approximately 100 mm in the three
10.7 Add about1gof specimen and reweigh the dish and
internal dimensions. Furnaces with larger internal dimensions
contents accurately. Record the results as W .
have been found to be unsuitable. The seal at the door must be
10.8 Place the weighed dish and contents into the muffle
free of gaping cracks or chips that will allow air into the
furnace and set the interval timer for 3 min.
furnace. A muffle furnace with bare heating wires on the floor
10.9 Aftertheelapsedtime,removethedishfromthemuffle
of the furnace must not be used without additional electrical
furnace and place it in the desiccator to cool for at least 2 min.
safety precautions.
Longer cooling periods do not affect the test.
6.3 Screen, 20-Mesh, approximately 120 by 100 mm. Fold
10.10 Reweigh the dish and remaining carbon black accu-
down approximately 10 mm of the long dimension to provide
rately. Record the results as W .
a raised platform to fit inside the muffle furnace. 3
10.11 Ifashablemineralfillersaresuspectedtobepresentin
6.4 Thermocouple-Probe Temperature Controller or
the compound, replace the dish and contents into the muffle
Equivalent—This may be an integral part of newer muffle
furnaceforaperiodof10minorlongeruntilonlylight-colored
furnaces or may be purchased separately to provide improved
ash remains.
control on older furnaces.
10.12 Transferthedishandcontentsfromthemufflefurnace
6.5 Desiccator (for example, 255 mm), with alumina or
to the desiccator and let it cool for 2 min.
equivalent desiccant.
10.13 Reweigh the dish and ash accurately. Re
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