ASTM D5594-18a(2024)
(Test Method)Standard Test Method for Determination of the Vinyl Acetate Content of Ethylene-Vinyl Acetate (EVA) Copolymers by Fourier Transform Infrared Spectroscopy (FT-IR)
Standard Test Method for Determination of the Vinyl Acetate Content of Ethylene-Vinyl Acetate (EVA) Copolymers by Fourier Transform Infrared Spectroscopy (FT-IR)
SIGNIFICANCE AND USE
5.1 Properties of EVA copolymers are affected by the amount of vinyl acetate incorporated in the copolymer: This test method provides a means to determine the vinyl acetate level in copolymer samples.
5.2 Before proceeding with this test method, reference should be made to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters, or a combination thereof, covered in the materials specification shall take precedence over those mentioned in this test method. If there are no material specifications, then the default conditions apply.
SCOPE
1.1 This test method covers infrared procedures for determining the vinyl acetate content of EVA copolymers using pressed films (Procedure A) or molded plaques (Procedure B) and internal corrections for sample thickness.
1.2 This test method is applicable to the analysis of EVA copolymers containing 0.5 to 55 % vinyl acetate except as specified in 1.3.
1.3 Talc interferes with the 1020 cm−1 vinyl acetate band. Resins containing
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.
Note 1: There is no known ISO equivalent to this standard.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D5594 − 18a (Reapproved 2024)
Standard Test Method for
Determination of the Vinyl Acetate Content of Ethylene-Vinyl
Acetate (EVA) Copolymers by Fourier Transform Infrared
Spectroscopy (FT-IR)
This standard is issued under the fixed designation D5594; 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 E168 Practices for General Techniques of Infrared Quanti-
tative Analysis
1.1 This test method covers infrared procedures for deter-
E177 Practice for Use of the Terms Precision and Bias in
mining the vinyl acetate content of EVA copolymers using
ASTM Test Methods
pressed films (Procedure A) or molded plaques (Procedure B)
E691 Practice for Conducting an Interlaboratory Study to
and internal corrections for sample thickness.
Determine the Precision of a Test Method
1.2 This test method is applicable to the analysis of EVA
IEEE/ASTM SI-10 Use of the International System of Units
copolymers containing 0.5 to 55 % vinyl acetate except as
(SI): The Modem Metric System
specified in 1.3.
E691 Practice for Conducting an Interlaboratory Study to
−1
Determine the Precision of a Test Method
1.3 Talc interferes with the 1020 cm vinyl acetate band.
Resins containing <5 % vinyl acetate and talc are excluded
2.2 ISO Standard:
from the scope of this test method.
ISO 8985 Plastics—Ethylene/Vinyl Acetate Copolymer
Thermoplastics—Determination of Vinyl Acetate
1.4 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are provided for
3. Terminology
information purposes only.
3.1 Definitions:
1.5 This standard does not purport to address all of the
3.1.1 Units, symbols, and abbreviations used in this test
safety concerns, if any, associated with its use. It is the
method appear in Terminology E131 or IEEE/ASTM SI-10.
responsibility of the user of this standard to establish appro-
3.2 Abbreviations:
priate safety, health, and environmental practices and deter-
3.2.1 EVA—ethylene-vinyl acetate copolymer.
mine the applicability of regulatory limitations prior to use.
Specific precautionary statements are given in Section 8. 3.2.2 PTFE—tetrafluorethylene polymer.
3.2.3 FT-IR—Fourier transform infrared.
NOTE 1—There is no known ISO equivalent to this standard.
1.6 This international standard was developed in accor-
4. Summary of Test Method
dance with internationally recognized principles on standard-
4.1 The vinyl acetate content is measured using infrared
ization established in the Decision on Principles for the
−1
absorption band at 1020 cm (0.5 to 5 % vinyl acetate) or 609
Development of International Standards, Guides and Recom-
−1
cm (5 to 55 % vinyl acetate).
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4.2 Sample thickness is measured internally using an ethyl-
−1
ene infrared absorption band at 720 cm (28 to 55 % vinyl
2. Referenced Documents
−1 −1
acetate), 2020 cm (0.5 to 28 % vinyl acetate), or 4250 cm
2.1 ASTM Standards:
(5 to 28 % vinyl acetate).
E131 Terminology Relating to Molecular Spectroscopy
4.3 Regression analysis is performed on vinyl acetate/
ethylene ratios versus known vinyl acetate contents for EVA
This test method is under the jurisdiction of ASTM Committee D20 on Plastics
copolymer standards. The resulting equation is used to calcu-
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved April 1, 2024. Published April 2024. Originally late the vinyl acetate content for subsequent EVA copolymer
approved in 1994. Last previous edition approved in 2018 as D5594 - 18a. DOI:
samples.
10.1520/D5594-18AR24.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
*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
D5594 − 18a (2024)
5. Significance and Use 8.3 Care shall be taken to avoid burns when handling dry
ice.
5.1 Properties of EVA copolymers are affected by the
amount of vinyl acetate incorporated in the copolymer: This
9. Specimen Preparation
test method provides a means to determine the vinyl acetate
9.1 Procedure A:
level in copolymer samples.
9.1.1 Control the hot-plate temperature at 250 6 10°C.
5.2 Before proceeding with this test method, reference
9.1.2 Place a microscope slide, containing a fraction of the
should be made to the specification of the material being tested.
sample pellet, on the hot-plate.
Any test specimen preparation, conditioning, dimensions, or
9.1.3 Cover the sample with another slide and press with a
testing parameters, or a combination thereof, covered in the
wooden pestle. Use film circular motions to press a uniform
materials specification shall take precedence over those men-
film.
tioned in this test method. If there are no material
9.1.4 Remove the microscope slide from the hot-plate and
specifications, then the default conditions apply.
quench the pressed polymer film by dipping the two slides into
a beaker of cold water. Remove the film and blot dry with an
6. Apparatus
absorbent towel.
6.1 Fourier Transform Infrared (FT-IR) Spectrophotometer,
9.1.5 Absorption maxima, measured on film produced by
equipped with a detector, which gives a linear response over
this procedure, shall not exceed 1.5 absorbance units for either
the desired concentration range, is capable of 4-cm resolution
of the analytical bands used.
−1
(nominal), and is able to scan from 4400 to 450 cm .
9.2 Procedure B:
NOTE 2—A DTGS detector has been found suitable for this application.
NOTE 3—Omit 9.2.1 to 9.2.11 for analysis of blown film.
6.2 Hot Plate, (Sample Preparation Procedure A only).
9.2.1 Select a brass or paper mold with a thickness appro-
6.3 Microscope Slides, (Sample Preparation Procedure A
priate to the vinyl acetate content of the sample. The absorption
only).
maxima of the vinyl acetate and ethylene bands measured on
the plaque are not to exceed 1.5 absorbance units.
6.4 Laboratory Press, capable of at least 9 000 kg (20 000
lb) 150°C (300°F), (Sample Preparation Procedure B only).
NOTE 4—To meet the absorbance requirement specified in 9.2.1 it will
be necessary to vary the mold thickness as the vinyl acetate content
6.5 Backing Plates, steel or aluminum (Sample Preparation
changes. The mold thickness required typically will be between 50 and
Procedure B only).
150 μm (2 to 6 mil).
6.6 Brass Shim Stock (Roll), 50 to 150 μm (2 to 6 mil) thick
9.2.2 Place a polyester sheet (or fiberglass impregnated
and 150 mm (6 in.) wide (Sample Preparation Procedure B
PTFE cloth) followed by a brass or paper mold on a backing
only).
plate.
6.7 Polyester Sheet, or fiberglass impregnated PTFE cloth
NOTE 5—For resins with vinyl acetate content ≥40 %, a PTFE film
(Sample Preparation Procedure B only).
should be placed on top of the brass mold, or, if using a paper mold, under
the paper.
6.8 PTFE Film (Sample Preparation Procedure B, resins
containing ≥40 % vinyl acetate only). 9.2.3 Place a quantity of sample, appropriate to the thick-
ness of the mold used, in the center of each opening in the
6.9 Templates, (mold) with 150 × 150 mm (6 × 6 in.) pieces
mold. Do not overfill the mold openings.
of paper or brass shim stock (item 6.6) containing cavities of a
size and shape appropriate for the sample holders used, and, if
NOTE 6—If flashing occurs, the brass mold and backing plates can be
cleaned with a nylon scrubbing pad.
applicable, sheets of items 6.7 and 6.8 (Sample Preparation
Procedure B only).
9.2.4 Place another piece of polyester sheet (or fiberglass
impregnated PTFE cloth) and a backing plate on top of the
6.10 Cooling Block, steel or aluminum, at least 150 × 150
sample.
mm (6 × 6 in.), approximately 25 mm (1 in.) thick, channeled
for cooling water (Sample Preparation Procedure B only).
NOTE 7—For resins with vinyl acetate content ≥40 %, a PTFE film
should be placed over the sample before the polyester sheet (or fiberglass
7. Materials
impregnated PTFE cloth).
7.1 EVA copolymer standards containing nominal vinyl
9.2.5 Place the resulting “sandwich” in the press with the
acetate concentrations of 0.5 to 55 %, by weight.
platens heated at 150 to 175°C.
9.2.6 Close the press until the top platen barely touches the
7.2 Dry ice (Sample Preparation B Procedure A only).
top plate and leave for sufficient time to permit the sample to
8. Hazards
soften and outgas.
8.1 Care shall be taken to avoid burns when handling
NOTE 8—Acceptable plaques, free of gas bubbles, have been obtained
microscope slides on the hot-plate (Sample Preparation Proce-
when the sample is allowed to soften for 3 min.
dure A), and gloves shall be worn when plaques are prepared
9.2.7 Close the press completely and apply at least 9 000 kg
using a heated press (Sample Preparation Procedure B).
(20 000 lb) force for approximately 1 min.
8.2 Care also shall be taken to avoid breaking the micro- 9.2.8 Cool the “sandwich” to room temperature, release the
scope slides while removing the pressed polymer film. pressure, and remove the “sandwich” from the press.
D5594 − 18a (2024)
9.2.9 In cases where the press does not have cooling 10.7 Calculate the vinyl acetate/ethylene area ratio for the
capability or where sample throughput needs to be increased, appropriate data reduction procedure defined in 12.1.
the following alternative to 9.2.8 may be used. The “sandwich” 10.7.1 For linear regression analysis:
is removed from the press hot and placed on a metal cooling
r 5 A /A (1)
va et
block through which cold water is circulated. A mass of at least
10.7.2 For nonlinear regression analysis:
4 kg (9 lb) is placed on top to the “sandwich” while it cools to
room temperature.
R 5 A /~A 1A ! (2)
va va et
9.2.10 For resins with vinyl acetate content <40 %, separate
where:
the backing plates and remove the plaques from the mold.
A = Area of vinyl acetate band, and
va
9.2.11 For resins with vinyl acetate content ≥40 %, place the
A = Area of ethylene band.
et
“sandwich” on dry ice for at least 15 s before separating the
backing plate, polyester sheet (or fiberglass impregnated PTFE
10.8 Repeat 10.2 through 10.7.2 for each standard EVA
cloth), and the PTFE film from the plaque.
copolymer film (plaque).
9.2.12 Select plaques that are clear and of uniform thickness
10.9 A minimum of five standards shall be used for the
for the FT-IR analysis.
linear regression of the 0.5 to 5.0 % vinyl acetate range. The
number of standards used for the nonlinear regression of either
10. Calibration
the 5.0 to 28 % or 28 to 55 % vinyl acetate ranges shall not be
10.1 Record the open beam background spectrum from
less than six.
−1 −1
4400 to 450 cm at a nominal resolution of 4 cm .
10.10 The standards must cover the full range of vinyl
10.2 Place a standard EVA copolymer film (plaque), pre-
acetates to be analyzed. Extrapolation is not permitted.
pared as described in 9.1 or 9.2, in the sample beam of the
11. Procedure
FT-IR spectrometer.
−1
11.1 Prepare samples as described in 9.1 for films or 9.2 for
10.3 Record the infrared spectrum from 4400 to 450 cm at
−1
plaques.
a nominal resolution of 4 cm . The signal-to-noise ratio, S/N,
should be acceptable for the desired precision. A typical EVA
11.2 Record the open beam background spectrum from
−1 −1
copolymer spectrum (9.0 % vinyl acetate) is shown in Fig. 1.
4400 to 450 cm at a nominal resolution of 4 cm .
10.4 Ratio the sample spectrum to the background spectrum
11.3 Place a sample film (plaque) in the sample beam of the
and convert the results to absorbance.
FT-IR spectrometer.
−1
10.5 Measure the area of one vinyl acetate band and one
11.4 Record the infrared spectrum from 4400 to 450 cm at
−1
ethylene band selected from the choices given in Table 1.
a nominal resolution of 4 cm . The signal-to-noise ratio, S/N,
Absorbance maxima for the analytical bands chosen are not to
should be acceptable for the desired precision.
exceed 1.5 absorbance units.
11.5 Ratio the sample spectrum to the background spectrum
10.6 Draw a baseline tangent to the absorption minima on
and convert the result to absorbance.
either side of each peak. Determine the area of each peak above
11.6 Measure the area of one vinyl acetate and one ethylene
the baseline.
band selected from the options given in Table 1. Absorbance
maxima for the analytical bands chosen are not to exceed 1.5
absorbance units.
11.7 Draw a baseline tangent to the absorption minima on
either side of each peak. Determine the area of each peak above
the baseline.
11.8 Calculate the vinyl acetate to ethylene area ratio as
specified in 10.7.
12. Calculation
12.1 Regression Analysis:
12.1.1 For vinyl acetate standards between 0.5 and 5.0 %,
use linear regression analysis to determine the calibration
equation of the data obtained in 10.7 and 10.8.
12.1.2 For vinyl acetate standards covering the range 5.0 to
28 % or 28 to 55 %, use nonlinear regression analysis, of the
data obtained in 10.7 and 10.8, to determine an equation of the
form:
Cole, K. C., Pellerius, T. E., D•••, M. M., and Paroli, R. M., “New Approach to
FIG. 1 FT-IR Spectrum of EVA Copolymer Standard (4.8 % Vinyl Quantitative Analysis of Two-Component Polymer Systems by Infrared
Acetate) Analyzed by Procedure B Spectroscopy,” Applied Spectroscopy, Vol 50, No. 6, June 1996, pp. 774–780.
D5594 − 18a (2024)
−1 −1
FIG. 2 Vinyl Acetate Correlation Curve (609 cm /1465 cm Height Ratio) Prepared Using Procedure B
−1 −1
TABLE 1 Vinyl Acetate Content (Weight %) Using 609 cm and 2019 cm Bands
Peak Height Measurements Peak Area Measurements
Sample
Average S S r R Average S S r R
r R r R
A 2.38 0.12 0.44 0.35 1.23 2.39 0.15 0.38 0.42 1.06
B 4.80 0.19 0.23 0.53 0.64 5.03 0.42 0.59 1.18 1.65
D 5.76 0.41 0.54 1.16 1.51 5.65 0.78 0.84 2.19 2.34
E 8.37 1.02 1.20 2.85 3.36 8.77 1.99 2.05 5.57 5.73
C 15.46 0.77 1.15 2.15 3.21 16.55 7.55 7.55 21.15 21.15
G 20.38 0.80 6.48 2.23 18.14 21.07 21.12 21.12 59.15 59.15
F 30.14 2.35 2.92 6.58 8.
...
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