ASTM D2839-96

Standard Test Method for Use of a Melt Index Strand for Determining Density of Polyethylene

SCOPE
1.1 This test method covers the preparation of a sample for polyethylene density determination in accordance with Test Method D 1505. The sample consists of a strand produced by extrusion of the polyethylene in accordance with Test Method D 1238, Condition 190/2.16 (Melt Index).  
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.  
Note 1-There is no similar or equivalent ISO standard.

General Information

• Status: Historical
• Publication Date: 09-Jul-1996
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.15 - Thermoplastic Materials

Relations

• Replaced By: ASTM D2839-02 - Standard Practice for Use of a Melt Index Strand for Determining Density of Polyethylene
• Effective Date: 10-Sep-2002

Standards Content (Sample)

Designation: D 2839 – 96 An American National Standard
Standard Test Method for
Use of a Melt Index Strand for Determining Density of
1
Polyethylene
This standard is issued under the fixed designation D 2839; 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 density by Test Method D 1505, for quality control purposes,
especially in a resin manufacturing facility where fast, repro-
1.1 This test method covers the preparation of a sample for
ducible, comparative results are needed. It is not necessarily
polyethylene density determination in accordance with Test
recommended for resin specifications which may be a part of a
Method D 1505. The sample consists of a strand produced by
sales contract between the buyer and the seller.
extrusion of the polyethylene in accordance with Test Method
4.2 The density of a polyethylene sample is highly depen-
D 1238, Condition 190/2.16 (Melt Index).
dent on the preparation and thermal history of the specimens.
1.2 The values stated in SI units are to be regarded as the
The level of density results obtained by this test method of
standard. The values given in parentheses are for information
sample preparation differs from that obtained by other methods
only.
as described in Practice D 1928.
1.3 This standard does not purport to address all of the
4.3 Before proceeding with this test method, reference
safety concerns, if any, associated with its use. It is the
should be made to the specification of the material being tested.
responsibility of the user of this standard to establish appro-
Any test specimen preparation, conditioning, dimensions, or
priate safety and health practices and determine the applica-
testing parameters, or some combination thereof, covered in
bility of regulatory limitations prior to use.
the materials specification shall take precedence over those
NOTE 1—There is no similar or equivalent ISO standard.
mentioned in this test method. If there are no material
specifications, the default conditions apply.
2. Referenced Documents
2.1 ASTM Standards:
5. Apparatus
D 1238 Test Method for Flow Rates of Thermoplastics by
5.1 Extrusion Plastometer, as described in Test Method
2
Extrusion Plastometer
D 1238.
D 1505 Test Method for Density of Plastics by the Density-
5.2 Hot Plate, to boil water.
2
Gradient Technique
5.3 Beakers, 250-mL low form, graduated, with watch-glass
D 1928 Practice for Preparation of Compression-Molded
covers.
2
Polyethylene Test Sheets and Test Specimens
E 691 Practice for Conducting an Interlaboratory Study to 6. Sample
3
Determine the Precision of a Test Method
6.1 Polyethylene, in any form suitable for test in accordance
with Test Method D 1238.
3. Terminology
3.1 Definitions: 7. Procedure
3.1.1 melt index strand—the extrudate produced when poly-
7.1 Prepare a Melt Index Strand by extruding the sample in
ethylene is extruded in accordance with Test Method D 1238,
accordance with Test Method D 1238, Condition 190/2.16,
Condition 190/2.16.
dropping the strand on a cool metal plate after cutting off.
When Procedure B of Test Method D 1238 is used, cut off the
4. Significance and Use
extrudate at about the time the timer is actuated and discard.
4.1 This test method has been found to be very useful for
Save the portion extruded during the timed interval.
preparing polyethylene samples suitable for determination of
NOTE 2—The conditioning procedure as described in 7.2 and 7.3 may
be omitted, if desired; in such case, after a 10-min cooling period, cut off
1
This test method is under the jurisdiction of ASTM Committee D-20 on Plastics
the density specimen as described in 7.4 and determine the density in
and is the direct responsibility of Subcommittee D20.12 on Olefin Plastics.
accordance with Test Method D 1505.
Current edition approved July 10, 1996. Published September 1996. Originally
7.2 Drop the strand into a 250-mL beaker containing at least
published as D 2839 – 69. Last previous edition D 2839 – 93.
This revision includes the addition of an ISO equivalency statement and
200 mL of briskly boiling water, and cover with a watch-glass.
precision and bias data.
Keep a large beaker full of water boiling along with this so that
2
Annual Book of ASTM Standards, Vol 08.01.
3 the amount of water can be maintained at 200 mL for the whole
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
1

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D 2839
TABLE 1 Precision Data
period without interrupting the boiling. Let the strand condition
A B C D
in the boiling water for 30 min. Material N Average S S r R
r R
B 10 0.9139 0.00026 0.00078 0.00072 0.00219
NOTE 3—A time interval of 5 days at room temperature between
...