ASTM D1921-06e1
(Test Method)Standard Test Methods for Particle Size (Sieve Analysis) of Plastic Materials
Standard Test Methods for Particle Size (Sieve Analysis) of Plastic Materials
SIGNIFICANCE AND USE
These test methods can be used to determine particle size distribution and therefore are useful for determining lot-to-lot uniformity.
The particle sizes of plastic materials affect the handling characteristics and sometimes will affect the processing characteristics of some polymers.
SCOPE
1.1 These test methods cover the measurement of the particle size of plastic materials in the powdered, granular, or pelleted forms in which they are commonly supplied. As these test methods utilize dry sieving, the lower limit of measurement is considered to be about 38 μm (No. 400 sieve). For smaller particle sizes, sedimentation test methods are recommended.
1.2 Two test methods are described:
1.2.1 Test Method A—This test method uses multiple sieves selected to span the particle size of the material. This method is used to determine the mean particle diameter and particle size distribution.
1.2.2 Test Method B—This test method is an abbreviated version of Test Method A conducted with a few specific sieves. This test method determines “percent passing” or “percent retained” on a given sieve. Test Method B is applicable to materials which do not have a normal particle size distribution such as pellets and cubes.
1.3 The values stated in SI units shall be considered standard for dimensions of the wire cloth openings and the diameter of the wires used in the wire cloth. The values stated in inch-pound units shall be considered standard with regard to the sieve frames.
1.4 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.
Note 1—There is no technically equivalent ISO standard.
General Information
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Standards Content (Sample)
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Designation: D1921 − 06
StandardTest Methods for
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Particle Size (Sieve Analysis) of Plastic Materials
This standard is issued under the fixed designation D1921; 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.
This standard has been approved for use by agencies of the Department of Defense.
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´ NOTE—Added research report information to Section 17 editorially in September 2010.
1. Scope* 2. Referenced Documents
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2.1 ASTM Standards:
1.1 These test methods cover the measurement of the
E11Specification forWovenWireTest Sieve Cloth andTest
particle size of plastic materials in the powdered, granular, or
Sieves
pelleted forms in which they are commonly supplied.As these
E691Practice for Conducting an Interlaboratory Study to
test methods utilize dry sieving, the lower limit of measure-
Determine the Precision of a Test Method
ment is considered to be about 38 µm (No. 400 sieve). For
smaller particle sizes, sedimentation test methods are recom-
3. Summary of Test Methods
mended.
3.1 A dry mass of plastic material is placed on a series of
1.2 Two test methods are described: sieves arranged in order of increasing fineness and the mass is
divided into fractions corresponding to the sieve opening.
1.2.1 Test Method A—This test method uses multiple sieves
selected to span the particle size of the material. This method
4. Significance and Use
is used to determine the mean particle diameter and particle
4.1 These test methods can be used to determine particle
size distribution.
size distribution and therefore are useful for determining
1.2.2 Test Method B—This test method is an abbreviated
lot-to-lot uniformity.
versionofTestMethodAconductedwithafewspecificsieves.
4.2 Theparticlesizesofplasticmaterialsaffectthehandling
This test method determines “percent passing” or “percent
characteristics and sometimes will affect the processing char-
retained” on a given sieve. Test Method B is applicable to
acteristics of some polymers.
materials which do not have a normal particle size distribution
such as pellets and cubes.
5. Interferences
1.3 The values stated in SI units shall be considered
5.1 Some materials develop a static charge during sieving.
standard for dimensions of the wire cloth openings and the This charge interferes with the sieving process and results in a
diameter of the wires used in the wire cloth. The values stated
coarse bias. Use of an antistat is necessary to obtain meaning-
ininch-poundunitsshallbeconsideredstandardwithregardto ful results.
the sieve frames.
5.2 The choice of antistat (or slip agent) has been known to
affect the coarse bias. Some materials are more effective in
1.4 This standard does not purport to address all of the
aiding the fines to separate from the mass.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5.3 Too much material on a sieve causes mass blinding and
priate safety and health practices and determine the applica- results in a coarse bias. The sieve selection and charge weight
bility of regulatory limitations prior to use. must be chosen to avoid overloading any sieve.
5.4 Wavy, improperly stretched wire-cloth may allow wires
NOTE 1—There is no technically equivalent ISO standard.
to separate without being visually damaged. Sieves with wavy
or torn wires shall not be used, as they no longer conform to
Specification E11.
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These test methods are under the jurisdiction of ASTM Committee D20 on
Plastics and are the direct responsibility of Subcommittee D20.70 on Analytical
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Methods (Section D20.70.01). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2006. Published June 2006. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1961. Last previous edition approved in 2001 as D1921-01. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D1921-06E01. the ASTM website.
*A Summary of Changes section appears at the end of this standard
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D1921 − 06
6. Apparatus 11.2 If possible, condition the material to the laboratory
temperature and humidity.
6.1 Balance,500-gminimumcapacitywiththecapabilityof
reading to the nearest 0.1 g.
TEST METHOD A
6.2 Mechanical Sieving Device and Time Switch—A me-
12. Procedure
chanicalsieve-shakingdeviceequippedwithanautomatictime
switch. This device shall be capable
...
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