Standard Test Method for Determining Molecular Weight Distribution and Molecular Weight Averages of Polyolefins by High Temperature Gel Permeation Chromatography

SIGNIFICANCE AND USE
This test method measures the molecular weight distribution and molecular weight averages of polyethylene (except LDPE) and polypropylene resins. Differences in molecular weight and molecular weight distribution significantly affect physical properties, such as morphology, strength, melt flow etc., and as a result, the final properties of products made from these resins.
SCOPE
1.1 This test method covers the determination of molecular weight distributions and molecular weight averages of linear polyolefins by high temperature gel permeation chromatography (GPC). This test method uses commercially available polystyrene standards and equipment and is applicable to polyethylenes (excluding high pressure low density polyethylene-LDPE) and polypropylenes soluble in 1,2,4-trichlorobenzene (TCB) at 140C. This test method is not absolute and requires calibration.Note 1
Size exclusion chromatography (SEC) often is used as an alternative name for gel permeation chromatography (GPC).Note 2
Specific methods and capabilities of users may vary with differences in columns, instrumentation, applications software, and practices between laboratories.Note 3
One general method is outlined herein; alternative analytical practices can be followed and are attached in notes where appropriate.Note 4
There is no similar or equivalent ISO standard.
1.2 The values stated in SI units, based on IEEE/ASTM S1-10, are to be regarded as the standard.
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.

General Information

Status
Historical
Publication Date
14-Mar-2006
Technical Committee
Drafting Committee
Current Stage
Ref Project

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ASTM D6474-99(2006) - Standard Test Method for Determining Molecular Weight Distribution and Molecular Weight Averages of Polyolefins by High Temperature Gel Permeation Chromatography
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D6474 −99(Reapproved 2006)
Standard Test Method for
Determining Molecular Weight Distribution and Molecular
Weight Averages of Polyolefins by High Temperature Gel
1
Permeation Chromatography
This standard is issued under the fixed designation D6474; 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 Molecular Weight Distribution of Polystyrene by High
Performance Size-Exclusion Chromatography
1.1 This test method covers the determination of molecular
E685 Practice for Testing Fixed-Wavelength Photometric
weight distributions and molecular weight averages of linear
Detectors Used in Liquid Chromatography
polyolefins by high temperature gel permeation chromatogra-
E691 Practice for Conducting an Interlaboratory Study to
phy (GPC). This test method uses commercially available
Determine the Precision of a Test Method
polystyrene standards and equipment and is applicable to
IEEE/ASTM S1-10 Standard for Use of the International
polyethylenes (excluding high pressure low density polyethyl-
System of Units (SI): The Modern System (replaces
ene–LDPE) and polypropylenes soluble in 1,2,4-
ASTM E 380 and ANSI/IEEE Standard 268-1992)
trichlorobenzene (TCB) at 140°C. This test method is not
absolute and requires calibration.
3. Terminology
NOTE 1—Size exclusion chromatography (SEC) often is used as an
3.1 Definitions—Definitions of terms applying to plastics
alternative name for gel permeation chromatography (GPC).
appear in Terminology D883.
NOTE 2—Specific methods and capabilities of users may vary with
differences in columns, instrumentation, applications software, and prac-
3.2 Definitions of Terms Specific to This Standard:
tices between laboratories.
3.2.1 polyolefin, n—used in this context,referstoPE(except
NOTE 3—One general method is outlined herein; alternative analytical
LDPE) and PP thermoplastics.
practices can be followed and are attached in notes where appropriate.
NOTE 4—There is no similar or equivalent ISO standard.
4. Summary of Test Method
1.2 The values stated in SI units, based on IEEE/ASTM
4.1 In this test method, a polyolefin sample is dissolved in a
S1-10, are to be regarded as the standard.
solvent and injected onto a chromatographic column(s) packed
1.3 This standard does not purport to address all of the
withasolidsubstrate,whichseparatesthemoleculesaccording
safety concerns, if any, associated with its use. It is the
to their size in solution. The separated molecules are detected
responsibility of the user of this standard to establish appro-
and recorded as they elute from the column according to
priate safety and health practices and determine the applica-
concentration. Through calibration, retention times are con-
bility of regulatory limitations prior to use.
verted to molecular weights.Average molecular weight param-
eters and molecular weight distribution are determined from
2. Referenced Documents
the molecular weight concentration data.
2
2.1 ASTM Standards:
5. Significance and Use
D883 Terminology Relating to Plastics
D3016 Practice for Use of Liquid Exclusion Chromatogra-
5.1 This test method measures the molecular weight distri-
phy Terms and Relationships
bution and molecular weight averages of polyethylene (except
D5296 Test Method for Molecular Weight Averages and
LDPE) and polypropylene resins. Differences in molecular
weight and molecular weight distribution significantly affect
physical properties, such as morphology, strength, melt flow
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
etc., and as a result, the final properties of products made from
and is the direct responsibility of Subcommitttee D20.70 on Analytical Methods.
these resins.
Current edition approved March 15, 2006. Published April 2006. Originally
approved in 1999. Last previous edition approved in 1999 as D6474–99 DOI:
6. Interferences
10.1520/D6474-99R06.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.1 Amajor interference is the presence of insoluble, highly
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
entangled,highmolecularweightmaterialthatmaybelinearor
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. cross-linked.Asuccessful outcome of the test requires that the
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1

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D6474−99 (2006)
sample be dissolved completely prior to the chromatographic 7.6 Detector—The detector provides a continu
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