ASTM D3168-85(2011)
(Practice)Standard Practice for Qualitative Identification of Polymers in Emulsion Paints
Standard Practice for Qualitative Identification of Polymers in Emulsion Paints
SIGNIFICANCE AND USE
Identification of specific acrylic polymers in emulsion paints is often difficult or impossible by infrared alone. This is particularly true when the acrylic is present in a small amount as a comonomer with vinyl acetate, or when blended with alkyds or other ester systems. If identification of an acrylic component is required in such a system, it may often be accomplished by gas-liquid chromatographic analysis of the pyrolyzed paint film. The presence of a number of other polymers may often also be confirmed by pyrolysis since they produce characteristic and reproducible pyrograms.
The pyrograms obtained from unknown samples vary in complexity according to the sample composition. It is necessary to establish the presence or absence of as many components as possible from a study of the infrared spectra obtained in the first part of this practice. The gas-liquid chromatography results may then be used to help identify any unknown components present and to confirm identifications made by infrared.
SCOPE
1.1 This practice describes a procedure for the qualitative identification in emulsion paints of most types of polymers present as major components of the paint vehicle. Limitations are discussed in Sections and .
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3168 −85(Reapproved 2011)
Standard Practice for
Qualitative Identification of Polymers in Emulsion Paints
This standard is issued under the fixed designation D3168; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope obtainedandcomparedwithreferencespectraforidentification
of major components.
1.1 This practice describes a procedure for the qualitative
identification in emulsion paints of most types of polymers 4.2 The paint is applied to a filament and pyrolyzed to
present as major components of the paint vehicle. Limitations depolymerizethevehicle.Aninternalstandardisaddedandthe
are discussed in Sections 5 and 10. pyrolyzate is separated into its components by gas-liquid
chromatography. Monomers are identified by comparison of
1.2 The values stated in SI units are to be regarded as the
relative retention times.
standard. The values given in parentheses are for information
only.
5. Significance and Use
1.3 This standard does not purport to address all of the
5.1 Identification of specific acrylic polymers in emulsion
safety concerns, if any, associated with its use. It is the
paints is often difficult or impossible by infrared alone. This is
responsibility of the user of this standard to establish appro-
particularly true when the acrylic is present in a small amount
priate safety and health practices and determine the applica-
as a comonomer with vinyl acetate, or when blended with
bility of regulatory limitations prior to use.
alkyds or other ester systems. If identification of an acrylic
component is required in such a system, it may often be
2. Referenced Documents
accomplished by gas-liquid chromatographic analysis of the
2.1 ASTM Standards:
pyrolyzed paint film. The presence of a number of other
D16TerminologyforPaint,RelatedCoatings,Materials,and
polymers may often also be confirmed by pyrolysis since they
Applications
produce characteristic and reproducible pyrograms.
D1193Specification for Reagent Water
5.2 Thepyrogramsobtainedfromunknownsamplesvaryin
D2621Test Method for Infrared Identification of Vehicle
complexity according to the sample composition. It is neces-
Solids From Solvent-Reducible Paints
sary to establish the presence or absence of as many compo-
E275PracticeforDescribingandMeasuringPerformanceof
nents as possible from a study of the infrared spectra obtained
Ultraviolet and Visible Spectrophotometers
inthefirstpartofthispractice.Thegas-liquidchromatography
results may then be used to help identify any unknown
3. Terminology
components present and to confirm identifications made by
3.1 Definitions—For definitions of terms, refer to Terminol-
infrared.
ogy D16.
6. Interferences
4. Summary of Practice
6.1 Dibutylmaleateanddibutylfumaratemonomersarenot
successfully recovered by this procedure. If their presence is
4.1 The vehicle is extracted from the dried paint and after
suspected as comonomer in a vinyl acetate copolymer system,
filtering is cast on a salt plate. The infrared spectrum is
n-butyl alcohol should be found in the pyrolyzate. This
evidence, together with the absence of butyl acrylate or butyl
methacrylate monomer peaks, is an indirect indication of the
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
presence of one or both of these monomers.
Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.
6.2 The presence of relatively low quantities of copolymer-
CurrenteditionapprovedJuly1,2011.PublishedJuly2011.Originallyapproved
ized acids may not be successfully established by this
in 1973. Last previous edition approved in 2005 as D3168–85(2005). DOI:
10.1520/D3168-85R11.
procedure, due to some unavoidable decomposition of acrylate
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and methacrylate esters to acrylic or methacrylic acid and the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
corresponding alcohols during the pyrolysis. The infrared
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. spectrum and an acid number determination, both run on the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3168−85 (2011)
polymer solids, may usually be relied upon to establish the 8.2 Purity of Water—Unless otherwise indicated, reference
presence or absence of acid groups in the polymer. towatershallbeunderstoodtomeanreagentwaterconforming
to Type II of Specification D1193.
6.3 In the case where the polymer being analyzed is simple
(such as a vinyl acetate-alkyl ester copolymer, or a single 8.3 Extraction Solvent Mixture—Equal volumes of o-
acrylate-methacrylate copolymer), it might be advantageous to dichlorobenzene, dimethylformamide, and tetrahydrofuran.
examine the total pyrolyzate directly by infrared (as a solution
8.4 Liquid Nitrogen.
in carbon disulfide).
8.5 Petroleum Ether (30 to 60°C boiling range) or heptane.
7. Apparatus
9. Procedure—Infrared Analysis
7.1 Spectrophotometer, recording, double-beam, infrared,
9.1 Transfer 1 to 2g of emulsion paint to a 100-mL
with a range from at least 2.5 µm to 15 µm and a spectral
borosilicate glass beaker. Add approximately 2 mL of water
resolutionofatleast0.04µmoverthatrange.Forcheckingthe
andswirloruseacleanglassrodtospreadthepaintuniformly
performance of the infrared spectrophotometer, see Practice
over the bottom of the beaker.
E275.
9.2 Place the beaker in an oven at 105 to 6 2°C for at least
7.2 Cell Mount, demountable.
2h, breaking up any skins that form so that complete drying is
7.3 Halide Salt Crystals, for use with demountable cell
ensured.
mount.
9.3 Add50mLofwater,coverwithawatchglass,andplace
7.4 Oven, gravity or forced-draft, maintained at 105 6 2°C.
on a steam bath or low-temperature hotplate for 1h. This
process removes emulsifiers, protective colloids, and other
7.5 Linear Programmed Temperature Gas Chromatograph,
water-soluble components that might interfere with interpreta-
equipped with a thermal conductivity detector.
tion of the infrared spectrum. Decant off the clear water layer
7.6 PyrolysisAccessory—Anysuitableapparatusforachiev-
and discard. If the addition of the distilled water to the dried
ing pyrolysis external to the chromatograph, that results in the
paint film produces a milky dispersion, the drying step in 9.2
recovery of sufficient pyrolyzate for identification purposes.
was not complete and should be repeated.
The apparatus described in theAnnex has been found to meet
NOTE 1—If there is an interest in characterization of the emulsifier
these requirements.
systemused,thewatershouldbefilteredthroughafine-texturefilterpaper
7.7 GasChromatographicColumn,3m(10ft)inlength,6.4
and taken to dryness. The solids may then be examined by infrared.
mm ( ⁄4 in.) in outside diameter copper tubing packed with
9.4 Dry for 15 to 20 min in an oven at 105 to 6 2°C. Add
10%siliconeresin on80to100-meshacid-washed,dimethyl-
50 mLof petroleum ether or heptane, cover with a watchglass,
dichlorosilane treated calcined diatomaceous earth.
and bring to a slow boil for approximately 5 min.This process
7.8 Steam Bath or Low-Temperature Hot Plate.
removes most emulsified plasticizers, oils, and other water
insoluble, nonpolymeric organic materials, which might also
7.9 Flask, small Dewar.
interfere with the interpretation of the infrared spectrum.
8. Reagents
Decant off the solvent and discard.
8.1 Purity of Reagents—Reagent grade chemicals shall be
NOTE 2—If there is an interest in characterizing the water-insoluble
used in all tests. Unless otherwise indicated, it is intended that petroleum ether-soluble fraction, it should also be filtered through
fine-texture paper, taken to dryness, and examined by infrared.
all reagents shall conform to the specifications of the Commit-
tee onAnalytical Reagents of theAmerican Chemical Society,
9.5 Add 10 mL of the extraction solvent mixture (8.3) and
where such specifications are available. Other grades may be
place on a steam bath or low-temperature hotplate for approxi-
used, provided it is first ascertained that the reagent is of
mately 1h. Filter, while still hot, through a fine-texture filter
sufficiently high purity to permit its use without lessening the
paper. If the polymer solution is viscous, it may be diluted
accuracy of the determination.
further with extraction solvent mixture and warmed prior to
filtration.Alternatively, the pigment may be removed from the
polymersolutionbycentrifuging.Evaporatethesolutiononthe
The sole source of supply of silicone resin SE-30, known to the committee at
this time is General Electric Co. If you are aware of alternative suppliers, please
steam bath or hotplate to a volume of 1 mL or less.
provide this information toASTM International Headquarters.Your comments will
9.6 Place the concentrated polymer solution on a halide salt
receive careful consideration at a meeting of the responsible technical committee,
which you may attend.
crystal and spread to form a uniform film.The thickness of the
The sole source of supply of Chromosorb W, known to the committee at this
film should be such that when the infrared spectrum is
time is Manville Sales Corp., Filtration and Minerals, P.O. Box 5108, Denver, CO
rec
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