ASTM D3168-85(1999)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D 3168 – 85 (Reapproved 1999)
Standard Practice for
Qualitative Identification of Polymers in Emulsion Paints
This standard is issued under the fixed designation D 3168; 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 pyrolyzate is separated into its components by gas-liquid
chromatography. Monomers are identified by comparison of
1.1 This practice describes a procedure for the qualitative
relative retention times.
identification in emulsion paints of most types of polymers
present as major components of the paint vehicle. Limitations
5. Significance and Use
are discussed in Sections 5 and 10.
5.1 Identification of specific acrylic polymers in emulsion
1.2 This standard does not purport to address all of the
paints is often difficult or impossible by infrared alone. This is
safety concerns, if any, associated with its use. It is the
particularly true when the acrylic is present in a small amount
responsibility of the user of this standard to establish appro-
as a comonomer with vinyl acetate, or when blended with
priate safety and health practices and determine the applica-
alkyds or other ester systems. If identification of an acrylic
bility of regulatory limitations prior to use.
component is required in such a system, it may often be
2. Referenced Documents accomplished by gas-liquid chromatographic analysis of the
pyrolyzed paint film. The presence of a number of other
2.1 ASTM Standards:
polymers may often also be confirmed by pyrolysis since they
D 16 Terminology for Paint, Related Coatings, Materials,
produce characteristic and reproducible pyrograms.
and Applications
5.2 The pyrograms obtained from unknown samples vary in
D 1193 Specification for Reagent Water
complexity according to the sample composition. It is neces-
D 2621 Test Method for Infrared Identification of Vehicle
sary to establish the presence or absence of as many compo-
Solids from Solvent-Reducible Paints
nents as possible from a study of the infrared spectra obtained
E 275 Practice for Describing and Measuring Performance
in the first part of this practice. The gas-liquid chromatography
of Ultraviolet, Visible, and Near Infrared Spectrophotom-
results may then be used to help identify any unknown
eters
components present and to confirm identifications made by
3. Terminology
infrared.
3.1 Definitions—For definitions of terms, refer to Terminol-
6. Interferences
ogy D 16.
6.1 Dibutyl maleate and dibutyl fumarate monomers are not
4. Summary of Practice successfully recovered by this procedure. If their presence is
suspected as comonomer in a vinyl acetate copolymer system,
4.1 The vehicle is extracted from the dried paint and after
n-butyl alcohol should be found in the pyrolyzate. This
filtering is cast on a salt plate. The infrared spectrum is
evidence, together with the absence of butyl acrylate or butyl
obtainedandcomparedwithreferencespectraforidentification
methacrylate monomer peaks, is an indirect indication of the
of major components.
presence of one or both of these monomers.
4.2 The paint is applied to a filament and pyrolyzed to
6.2 The presence of relatively low quantities of copolymer-
depolymerizethevehicle.Aninternalstandardisaddedandthe
ized acids may not be successfully established by this proce-
dure, due to some unavoidable decomposition of acrylate and
This practice is under the jurisdiction of ASTM Committee D-1 on Paint and
methacrylate esters to acrylic or methacrylic acid and the
Related Coatings, Materials, and Applications and is the direct responsibility of
corresponding alcohols during the pyrolysis. The infrared
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.
spectrum and an acid number determination, both run on the
Current edition approved Oct. 25, 1985. Published December 1985. Originally
e1
polymer solids, may usually be relied upon to establish the
published as D 3168 – 73. Last previous edition D 3168 – 73 (1979) .
Annual Book of ASTM Standards, Vol 06.01.
presence or absence of acid groups in the polymer.
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 3168
6.3 In the case where the polymer being analyzed is simple 8.3 Extraction Solvent Mixture—Equal volumes of o-
(such as a vinyl acetate-alkyl ester copolymer, or a single dichlorobenzene, dimethylformamide, and tetrahydrofuran.
acrylate-methacrylate copolymer), it might be advantageous to 8.4 Liquid Nitrogen.
examine the total pyrolyzate directly by infrared (as a solution 8.5 Petroleum Ether (30 to 60°C boiling range) or heptane.
in carbon disulfide).
9. Procedure—Infrared Analysis
7. Apparatus
9.1 Transfer 1 to 2 g of emulsion paint to a 100-mL
7.1 Spectrophotometer, recording, double-beam, infrared,
borosilicate glass beaker. Add approximately 2 mL of water
with a range from at least 2.5 µm to 15 µm and a spectral
and swirl or use a clean glass rod to spread the paint uniformly
resolution of at least 0.04 µm over that range. For checking the
over the bottom of the beaker.
performance of the infrared spectrophotometer, see Practice
9.2 Place the beaker in an oven at 105 to 62°C for at least
E 275.
2 h, breaking up any skins that form so that complete drying is
7.2 Cell Mount, demountable.
ensured.
7.3 Halide Salt Crystals, for use with demountable cell
9.3 Add 50 mLof water, cover with a watchglass, and place
mount.
on a steam bath or low-temperature hotplate for 1 h. This
7.4 Oven, gravity or forced-draft, maintained at 105 6 2°C.
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 Pyrolysis Accessory—Any suitable apparatus for
and discard. If the addition of the distilled water to the dried
achieving pyrolysis external to the chromatograph, that results
paint film produces a milky dispersion, the drying step in 9.2
in the recovery of sufficient pyrolyzate for identification
was not complete and should be repeated.
purposes.TheapparatusdescribedintheAnnexhasbeenfound
NOTE 1—If there is an interest in characterization of the emulsifier
to meet these requirements.
system used, the water should be filtered through a fine-texture filter paper
7.7 Gas Chromatographic Column, 10 ft (3 m) in length,
and taken to dryness. The solids may then be examined by infrared.
⁄4in. (6.4 mm) in outside diameter copper tubing packed with
9.4 Dry for 15 to 20 min in an oven at 105 to 62°C.Add 50
10 %siliconeresin on80to100-meshacid-washed,dimethyl-
mLofpetroleumetherorheptane,coverwithawatchglass,and
dichlorosilane treated calcined diatomaceous earth.
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
7.9 Flask, small Dewar.
insoluble, nonpolymeric organic materials, which might also
8. Reagents
interfere with the interpretation of the infrared spectrum.
Decant off the solvent and discard.
8.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
NOTE 2—If there is an interest in characterizing the water-insoluble
all reagents shall conform to the specifications of the Commit-
petroleum ether-soluble fraction, it should also be filtered through
tee onAnalytical Reagents of theAmerican Chemical Society, fine-texture paper, taken to dryness, and examined by infrared.
where such specifications are available. Other grades may be
9.5 Add 10 mL of the extraction solvent mixture (8.3) and
used, provided it is first ascertained that the reagent is of
place on a steam bath or low-temperature hotplate for approxi-
sufficiently high purity to permit its use without lessening the
mately 1 h. Filter, while still hot, through a fine-texture filter
accuracy of the determination.
paper. If the polymer solution is viscous, it may be diluted
8.2 Purity of Water—Unless otherwise indicated, reference
further with extraction solvent mixture and warmed prior to
to water shall be understood to mean reagent water conforming
filtration.Alternatively, the pigment may be removed from the
to Type II of Specification D 1193.
polymersolutionbycentrifuging.Evaporatethesolutiononthe
steam bath or hotplate to a volume of 1 mL or less.
5 9.6 Place the concentrated polymer solution on a halide salt
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 alternaive suppliers, please crystal and spread to form a uniform film. The thickness of the
provide this information to ASTM Headquarters. Your comments will receive
film should be such that when the infrared spectrum is
careful consideration at a meeting of the responsible technical committee, which
recorded, the transmittance of the strongest
...