ASTM D5576-00

Standard Practice for Determination of Structural Features in Polyolefins and Polyolefin Copolymers by Infrared Spectroscopy (FT-IR)

SCOPE
1.1 This practice describes infrared procedures for determining the molecular structural entities in the polyolefin chains (their quantitative levels with internal (Procedure A) and external (Procedure B) evaluation for sample thickness are suggested in the Appendix). The structural entities of primary concern are the types and distribution of branches. Although this practice centers its attention on polyolefins, the techniques, with proper modification, can be used for some other polymers as well.  
1.2 Often these structural entities are at a level of less than 2%. Higher concentration of branching systems may be treated in other methods that address a specific problem associated with entities between 2 and 49%.  
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. Specific hazards statements are given in Section 8.  Note 1-There is no similar or equivalent ISO standard.

General Information

• Status: Historical
• Publication Date: 09-Mar-2000
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.70 - Analytical Methods

Relations

• Replaced By: ASTM D5576-00(2006) - Standard Practice for Determination of Structural Features in Polyolefins and Polyolefin Copolymers by Infrared Spectrophotometry (FT-IR)
• Effective Date: 01-Sep-2006
• Referred By: ASTM D6645-18 - Standard Test Method for Methyl (Comonomer) Content in Polyethylene by Infrared Spectrophotometry
• Effective Date: 10-Mar-2000

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D 5576 – 00
Standard Practice for
Determination of Structural Features in Polyolefins and
Polyolefin Copolymers by Infrared Spectrophotometry
(FT-IR)
This standard is issued under the fixed designation D 5576; 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 * Fourier Transform Infrared Spectroscopy (FT-IR)
D 6248 Test Method for Vinyl and Trans Unsaturation in
1.1 Thispracticecoversinfraredproceduresfordetermining
Polyethylene by Infrared Spectrophotometry
the molecular structural features in polyolefins and polyolefin
E 131 Terminology Relating to Molecular Spectroscopy
copolymers. The structural features of primary concern are the
E 168 Practices for General Techniques of Infrared Quan-
types and numbers of branches. Although this practice centers
titative Analysis
its attention on polyolefins and polyolefin copolymers, the
E 932 Practice for Describing and Measuring Performance
techniques, with proper modification, can be used for some
of Dispersive Infrared Spectrophotometers
other polymers as well.
E 1421 Practice for Describing and Measuring Perfor-
NOTE 1—Quantitative determinations require either an internal or an
mance of Fourier Transform Infrared (FT-IR) Spectrom-
external evaluation of sample thickness.ASTM test methods available for
eters: Level Zero and Level One Tests
specific features are listed in Tables 1 and 2.
IEEE/ASTM SI–10 Standard for Use of the International
1.2 This standard does not purport to address all of the
System of Units (SI): The Modern System
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
priate safety and health practices and to determine the
3.1 Definitions— For definitions of plastics terms used in
applicability of the regulatory limitations prior to use.
this practice see Terminology D 883 and D 1600.
3.2 Units, symbols and abbreviations used in this practice
NOTE 2—There is no similar or equivalent ISO standard.
appear in Terminology E 131 or IEEE/ASTM SI-10.
2. Referenced Documents
4. Summary of Practice
2.1 ASTM Standards:
4.1 Infrared absorption bands suitable for quantitative
D 883 Terminology Relating to Plastics
analysis by FT-IR are listed in Tables 1 and 2. These are only
D 1505 Test Method for Density of Plastics by the Density-
typical bands and are not to be construed as exhaustive.
Gradient Technique
4.2 For quantitative determinations, sample specimen thick-
D 1600 Terminology of Abbreviated Terms Relating to
ness is measured internally at some band representing the basic
Plastics
–1
chain structure, such as 2019 cm for polyethylene, or
D 2238 Test Methods forAbsorbance of Polyethylene Due
–1 2
externally using a micrometer (see Tables 1 and 2 for ASTM
to Methyl Groups at 1378 cm
test methods).
D 3124 Test Method for Vinylidene Unsaturation in Poly-
ethylene by Infrared Spectrophotometry
NOTE 3—Warning: Molding can cause carbonyl formation due to
–1
D 3594 Test Method for Copolymerized Ethyl Acrylate in
oxidation. This should be checked in the 1700 to 1750 cm range.
Ethylene-Ethyl Acrylate
5. Significance and Use
D 5594 Test Method for Determination of Vinyl Acetate
Content of Ethylene-Vinyl Acetate (EVA) Copolymers by 5.1 The structural features expressed by these determina-
tions affect the ultimate polymeric properties and are useful in
showing correlations with many performance properties.
This practice is under the jurisdiction ofASTM Committee D20 on Plastics and
is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved March 10, 2000. Published June 2000. Originally
published as D 5576 – 94. Last previous edition D 5576 – 94. Annual Book of ASTM Standards, Vol 08.03.
2 5
Annual Book of ASTM Standards, Vol 08.01. Annual Book of ASTM Standards, Vol 03.06.
3 6
Annual Book of ASTM Standards, Vol 08.02. Annual Book of ASTM Standards, Vol 14.02.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5576
TABLE 1 Polyolefin Structural Features Determined by FT-IR
9.1.1.1 Control the hot plate temperature at 100 6 10°C
–1
Structure Absorption Band, cm ASTM Test Method above the melting temperature of the polymer.
9.1.1.2 Place a portion of the sample on a microscope slide
Methyl group (polyethylene) 1378 D 2238
Methyl group (eth-prop copol) 1380
on the hot plate.
Pendant methyl 935
9.1.1.3 Cover the sample with another slide and press with
Terminal vinyl 908 D 6248
a wooden pestle. Use firm circular motions to press a uniform
Trans-vinylene 965 D 6248
Vinylidene 888 D 3124
film.
9.1.1.4 To quench the pressed polymer film, dip the two
slides carefully into a beaker of cold water. Remove the film
TABLE 2 Structural Features in Polyolefin Copolymer
and blot dry.
Determined by FT-IR
9.1.2 Procedure B:
–1
Structure Absorption Band, cm ASTM Test Method
9.1.2.1 Preheat the press to about 50°C above the melting
Vinyl acetate 609 D 5994
point of the polymer.
1020 D 5994
9.1.2.2 Place a brass shim on the sheet material chosen (see
3270 D 5994
Styrene 770–700
7.1) that, in turn, covers a metal plate.
1600–1500
9.1.2.3 Add polymer in sufficient quantity to completely fill
Ethyl acrylate 1640–1730
862 D 3594 the shim aperture during pressing.
Ethylene acrylate 1280–1200
9.1.2.4 Cover with another piece of sheet (see 7.1) and
1640–1625
anoth
...