ASTM D2124-99e1
(Test Method)Standard Test Method for Analysis of Components in Poly(Vinyl Chloride) Compounds Using an Infrared Spectrophotometric Technique
Standard Test Method for Analysis of Components in Poly(Vinyl Chloride) Compounds Using an Infrared Spectrophotometric Technique
SCOPE
1.1 This test method provides for the identification of certain resins, plasticizers, stabilizers, and fillers in poly(vinyl chloride) (PVC) compounds by an infrared spectrophotometric technique. In many cases, individual components may be measured quantitatively. Complementary procedures, such as chromatographic and other separations, will be necessary to separate specific components and extend the applications of this test method. Other instrumental test methods, such as optical emission or X-ray spectroscopic methods, may yield complementary information which may allow more complete or, in some cases, easier measurement of the components. The resin components covered in this test method are listed in the appendix.
1.2 PVC formulations are too varied to be covered adequately by a single test method. Using the following test method, many compounds may be separated into resins, plasticizers, stabilizers, and fillers. A number of components can be quantitatively measured. Many more can be identified and their concentrations estimated. By the use of prepared standards, one may determine the usefulness and accuracy of the test method for specific PVC formulations. This test method is applicable for the resin components listed in the appendix and for other components having similar chemical compositions and solubility characteristics. This test method can lead to error in cases where the nature of the components is not known.
1.3 The values stated in SI units are to be regarded as the standard. The values in parentheses are given for information only.
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 similar or equivalent ISO standard.
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e1
Designation: D 2124 – 99
Standard Test Method for
Analysis of Components in Poly(Vinyl Chloride) Compounds
Using an Infrared Spectrophotometric Technique
This standard is issued under the fixed designation D 2124; 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.
e NOTE—Editorially removed obsolete item from the References section in April 2002.
NOTE 1—There is no similar or equivalent ISO standard.
1. Scope *
1.1 This test method provides for the identification of
2. Referenced Documents
certain resins, plasticizers, stabilizers, and fillers in poly(vinyl
2.1 ASTM Standards:
chloride) (PVC) compounds by an infrared spectrophotometric
E 131 Terminology Relating to Molecular Spectroscopy
technique. In many cases, individual components may be
E 168 Practices for General Techniques of Infrared Quanti-
measured quantitatively. Complementary procedures, such as
tative Analysis
chromatographic and other separations, will be necessary to
E 177 Practice for Use of the Terms Precision and Bias in
separate specific components and extend the applications of
ASTM Test Methods
this test method. Other instrumental test methods, such as
E 275 Practice for Describing and Measuring Performance
optical emission or X-ray spectroscopic methods, may yield
of Ultraviolet, Visible, and Near Infrared Spectrophotom-
complementary information which may allow more complete
eters
or, in some cases, easier measurement of the components. The
resin components covered in this test method are listed in the
3. Terminology
appendix.
3.1 Definitions:
1.2 PVC formulations are too varied to be covered ad-
3.1.1 For definitions related to the material on infrared
equately by a single test method. Using the following test
spectroscopy, refer to Terminology E 131.
method, many compounds may be separated into resins,
plasticizers, stabilizers, and fillers. A number of components
4. Summary of Test Method
can be quantitatively measured. Many more can be identified
4.1 The PVC compound is solvent-extracted in order to
and their concentrations estimated. By the use of prepared
separate the plasticizer from the compound. The resin is
standards, one may determine the usefulness and accuracy of
dissolved from the remaining compound and the inorganic
the test method for specific PVC formulations. This test
fillers and stabilizers separated by centrifuging. By this tech-
method is applicable for the resin components listed in the
nique, the compound is separated into (1) plasticizers, (2) resin,
appendix and for other components having similar chemical
and (3) inorganic stabilizers and fillers. Each may be individu-
compositions and solubility characteristics. This test method
ally analyzed by an infrared technique to identify and measure
can lead to error in cases where the nature of the components
the components.
is not known.
1.3 The values stated in SI units are to be regarded as the
5. Significance and Use
standard. The values in parentheses are given for information
5.1 PVC compounds are used in a wide variety of products
only.
and hence they are formulated to provide a wide range of
1.4 This standard does not purport to address all of the
physical properties. The physical properties required in a
safety concerns, if any, associated with its use. It is the
compound depend upon the product in which it is used. These
responsibility of the user of this standard to establish appro-
properties are largely determined by the type, quantity, and
priate safety and health practices and determine the applica-
quality of the compounding ingredients. The analytical test
bility of regulatory limitations prior to use.
method described below makes use of infrared spectrophotom-
etry for the qualitative or quantitative determination, or both, of
many of these ingredients in PVC compounds. This test
This test method is under the jurisdiction of ASTM Committee D-20 on Plastics
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods
(Section D20.70.08).
Current edition approved July 10, 1999. Published September 1999. Originally Annual Book of ASTM Standards, Vol 03.06.
published as D 2124 – 62. Last previous edition D 2124 – 70 (1994). 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 2124
method may be used for a variety of applications including sufficiently high purity to permit its use without lessening the
process control, raw material acceptance, product evaluation, accuracy of the determination.
and determination of changes in composition resulting from
7.2 Alumina, absorption.
environmental testing. 7.3 Carbon Disulfide (CS ).
5.2 This test method is directly applicable only to those
7.4 Ether, anhydrous.
components listed in the appendix and to those components
7.5 Potassium Bromide, (KBr) infrared quality.
which are known to be similar in chemical composition and in
7.6 Tetrachloroethane, technical.
solubility characteristics to the chemicals listed in the appen-
7.7 Tetrahydrofuran (stabilized with 0.1 % hydroquinone).
dix.
8. Component Separations
6. Apparatus
8.1 Initial Sample Preparation—Any test method that will
6.1 Initial Sample Preparation—Use any of the following
increase the surface area of a sample sufficiently to permit
apparatus, depending on shape and size of sample, for reducing
complete plasticizer extraction in a reasonable time is satisfac-
solid samples to small particle sizes:
tory. PVC compounds as received are usually in the form of
6.1.1 Pencil Sharpener or grater and a cold box or con-
powders, granules, slabs, or offshaped pieces. Powders may be
tainer capable of maintaining at least the temperature of solid
used directly. Thin sheets, 0.02 to 0.05-mm thick, molded from
carbon dioxide.
individual granules may be used. Granules may be pressed into
6.1.2 Grinding Wheel, coarse.
slabs. Slabs or appropriately shaped pieces may be treated by
6.1.3 Microtome.
one of the following techniques:
6.1.4 Grinding or Cutting Mills, commercial, for example, a
8.1.1 Buffing on a coarse grinding wheel,
Wiley mill (for samples larger than 1 g).
8.1.2 Cooling the sample with solid carbon dioxide and
6.2 Soxhlet Extraction Apparatus:
grinding the brittle sample in a clean pencil sharpener or on a
6.2.1 For 0.5 and 1.0-g samples, use an extraction apparatus
grater or clean file, or
with a 150-mL flask and a 27 by 100-mm thimble.
8.1.3 Shaving thin slices from the sample with a microtome.
6.2.2 For 0.2-g samples, use an extraction apparatus with a
8.2 Plasticizer Extraction—Weigh to 60.2 mg approxi-
30-mL flask and a 10 by 50-mm thimble.
mately1goffine particle size sample into a 27 by 100-mm
6.3 Mold and Press for KBr Pellets—A mold assembly
paper extraction thimble. Place the thimble in a jacketed
capable of pelletizing a 12.7-mm ( ⁄2-in.) minimum diameter
Soxhlet apparatus fitted with a tared 150-mL flask, and extract
pellet under vacuum and a press capable of exerting pressures
with 120 mL of ethyl ether for 6 h (Note 2). Remove the tared
of at least 140 MPa (20 000 psi) are required to press clear KBr
150-mL flask, containing the ethyl ether and the extracted
pellets.
plasticizer, from the jacketed Soxhlet apparatus and gently heat
6.4 Infrared Spectrophotometer—The spectral region from
to boil off the ethyl ether. Place the flask in an evacuated
−1
4000 to 650 cm (2.5 to 15 μm) is used. Refer to Practice
desiccator for a minimum of1hto remove the last traces of
E 275, with particular emphasis on Sections 5 and 14 relating
ethyl ether. Weigh to 60.2 mg the flask containing the
to resolution and spectral slit width measurements. An ultimate
extracted plasticizers. Calculate the percentage of plasticizers
4 −1 −1
resolving power (1) of at least 1.5 cm at 850 cm (0.02 μm
in the PVC sample as follows:
at 12 μm) is satisfactory. The suitability of the instrument
weight of extracted plasticizers 3 100
should be proven in the user’s laboratory. Demountable cells,
plasticizers, % 5
weight of PVC sample
1.0-mm liquid cells, and a KBr pellet holder are the accessories
used.
8.2.1 Keep the plasticizers for infrared identification or
6.5 Infrared Spectrophotometer, Fourier Transform (FT-IR), determination (8.4).
capable of attaining a 4 wave number resolution.
NOTE 2—Organometallic or organic stabilizer, if present, may partially
or wholly separate from either the plasticizer or resin components and
7. Reagents
should be considered when examining these compounds.
7.1 Purity of Reagents—Reagent grade chemicals shall be
8.3 Separation of Stabilizers and Fillers—Empty the resin,
used in all tests. Unless otherwise indicated, it is intended that
stabilizers, and fillers remaining in the extraction thimble into
all reagents shall conform to the specifications of the Commit-
a 50-mL beaker. Add 20 mL of tetrachloroethane and heat the
tee on Analytical Reagents of the American Chemical Society,
sample gently until the resin has dissolved. Wash the contents
where such specifications are available. Other grades may be
of the beaker quantitatively into a tared 50-mL centrifuge tube
used, provided it is first ascertained that the reagent is of
with 20 mL of tetrahydrofuran (which has been previously
passed through a 150 by 12.7-mm (6 by ⁄2-in.) diameter
alumina absorption column to remove hydroquinone), swirl to
The boldface numbers in parentheses refer to the list of references at the end of
mix, and centrifuge for 30 min. Decant the resin solution and
this test method.
reserve for infrared analysis. Wash the residue remaining in the
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
tared centrifuge tube with 20 mL of tetrahydrofuran and
listed by the American Chemical Society, see Analar Standards for Laboratory
centrifuge again for 30 min. Decant the solution containing the
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
remaining resin. Repeat the operation. Dry the tared centrifuge
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. tube containing the stabilizer and filler in an oven at 110°C for
D 2124
1 h, cool, weigh, and calculate the percentage of inorganic plasticizers is left to the discretion of the user. At the analytical
stabilizer and filler as follows: band frequency (wavelength) chosen, absorbances for the
sample spectrum (A + A ) and the blank spectrum (A ) are
weight of stabilizer and filler 3 100 s b b
inorganic stabilizer and filler, % 5
measured. Net absorbance due to sample component A is
weight of PVC sample s
(A + A )− A .
s b b
8.3.1 Keep the stabilizer and filler for infrared analysis.
9.3.3 Prepare plasticizer standards by dissolving the pure
Usually carbon black and color pigments are included in this
plasticizers of interest in CS to give a series of standard
portion.
solutions covering the 3.0 to 0.5-mg/mL range for each
8.4 Resin—Calculate the percentage of resin by difference
plasticizer. Run these standard plasticizer solutions under
(100 minus the total percent of plasticizers, stabilizers, and
conditions identical to those under which the samples are run
fillers).
to obtain the net absorbances of the components at a series of
concentrations. Plot Beer’s law curves of net absorbances
9. Infrared Analysis of Extracted Plasticizers
versus concentrations in milligrams per millilitre for each
9.1 The extracted plasticizers may be run on the infrared
component. All quantitative manipulations shall be in accor-
spectrophotometer as liquid films for identification or in CS
2 dance with Practices E 168.
solution for quantitative determinations.
9.3.4 Use the net absorbance of a specific plasticizer in
9.2 Identification of Plasticizers—Most plasticizers for
conjunction with the appropriate Beer’s law curve to determine
PVC compounds are liquid at room temperature. A few
the concentration in milligrams per millilitre.
secondary plasticizers may be solid but would be suspended or
9.3.5 Calculate the percentage of plasticizer in the PVC
dissolved in primary plasticizers. A demountable cell with
compound as follows:
NaCl windows and a 0.025-mm spacer usually suffices to give
specific plasticizer, % 5 ~AB/3W! 3 100
a strong plasticizer spectrum (1). Scan the spectrum from 4000
−1 −1
cm to 650 cm (2.5 to 15 μm). By reference to a collection
where:
of plasticizer spectra the plasticizers in the sample may be
A = concentration of plasticizer, mg/mL,
identified (2, 3, 4, 5, 6, 7, 8). With experience, rough estimates B = total weight of extracted plasticizers, mg, and
W = weight of PVC sample, mg.
of concentrations may be made to enable preparation of
matching standards for quantitative analysis.
10. Direct Infrared Determination of Plasticizers
9.3 Quantitative Analysis of Plasticizers—The variety of
plasticizers and their possible combinations in PVC com- 10.1 The use of this procedure usually presupposes that a
pounds is extensive. It is impossible to specify a single
complete formulation analysis is not required and that the
procedure that determines quantitatively all plasticizers with plasticizers to be determined are known.
equal precision and bias. The following procedure is useful for
10.2 Weigh 0.25 g (60.25 mg) of fine particle size sample
a number of plasticizers and their combinations, particularly if into a 10 by 50-mm extraction thimble. Place the thimble in a
either dioctyl phthalate or tricresyl phosphate is the primary
micro Soxhlet extraction apparatus. Extract for 6 h with 20 mL
plasticizer. The user should decide whether the efficiency,
of CS . Transfer the CS containing the extracted plasticizers to
2 2
precision, and bias of the procedure is satisfactory for a specific
a 25-mL volumetric flask, dilute to the mark with CS , and mix
combination of plasticizers to be analyzed.
thoroughly. Run this solution on the infrared spectrophotom-
9.3.1 Weigh 60 6 0.2 mg of extracted plasticizer (from 8.2)
eter. Instrumental conditions and techniques, preparation of
into a 25-mL Erlenmeyer flask equipped with a glass stopper;
standards, and Beer’s law curves are the same as those
add 20.00 mL of CS to dissolve the plasticizers. Take care to
specified in 9.2.
avoid loss of solvent by keeping the Erlenmeyer flask stop-
10.3 Calculation—Calculate the percentage of a specific
pered
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