ASTM D4671-05(2010)e1
(Test Method)Standard Test Method for Polyurethane Raw Materials Determination of Unsaturation of Polyols
Standard Test Method for Polyurethane Raw Materials Determination of Unsaturation of Polyols
SIGNIFICANCE AND USE
These test methods are suitable for quality control, as specification tests, and for research.
Side reactions that form unsaturated compounds in polypropylene oxides produce small amounts of polymers with only one hydroxyl group per chain. These unsaturated polymers lower functionality and molecular weight, while broadening the overall molecular-weight distribution.
SCOPE
1.1 These test methods measure unsaturation in polyether polyols. (See Note 1.)
1.1.1 Test Method A, High-Volume Reagent Method—Uses about 50 mL of 0.1 M mercuric acetate reagent in methanol and 15 g or more of sample. These test methods use an indicator for colorimetric determination of an end point. It is recommended for polyols with low values (below 0.01 millequivalents per gram (meq/g)) of unsaturation where large sample sizes are required.
1.1.2 Test Method B, Low-Volume Reagent Method—Uses 2 mL of ca. 0.05 M mercuric acetate reagent in methanol and about 1 g of sample or less. These test methods use a potentiometric determination of an end point.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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.
Note 1—There is no known ISO equivalent to this standard.
General Information
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
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Designation: D4671 − 05(Reapproved2010)
Standard Test Methods for
Polyurethane Raw Materials: Determination of Unsaturation
of Polyols
This standard is issued under the fixed designation D4671; 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.
ε NOTE—Reapproved with editorial changes in July 2010.
1. Scope Methods for Analysis and Testing of Industrial and Spe-
cialty Chemicals (Withdrawn 2009)
1.1 These test methods measure unsaturation in polyether
polyols. (See Note 1.)
3. Terminology
1.1.1 Test Method A, High-Volume Reagent Method—Uses
3.1 Definitions—For definitions of terms used in these test
about50mLof0.1 Mmercuricacetatereagentinmethanoland
methods, see Terminology D883.
15gormoreofsample.Thesetestmethodsuseanindicatorfor
colorimetric determination of an end point. It is recommended
4. Summary of Test Method
for polyols with low values (below 0.01 millequivalents per
4.1 Carbon-to-carbon unsaturated compounds in the sample
gram (meq/g)) of unsaturation where large sample sizes are
arereactedwithmercuricacetateandmethanolinamethanolic
required.
solution to produce acetoxymercuricmethoxy compounds and
1.1.2 Test Method B, Low-Volume Reagent Method—Uses 2
acetic acid. The amount of acetic acid released in this
mL of ca. 0.05 M mercuric acetate reagent in methanol and
equimolar reaction, which is determined by titration with
about1gof sample or less. These test methods use a
standard alcoholic potassium hydroxide, is a measure of the
potentiometric determination of an end point.
unsaturation originally present. Because the acid cannot be
1.2 The values stated in SI units are to be regarded as
titrated in the presence of excess mercuric acetate, due to the
standard. No other units of measurement are included in this
formation of insoluble mercuric oxide, sodium bromide is
standard.
added to convert the mercuric acetate to the bromide, which
1.3 This standard does not purport to address all of the
does not interfere. Inasmuch as these test methods are based on
safety concerns, if any, associated with its use. It is the
an acidimetric titration, a suitable correction must be applied if
responsibility of the user of this standard to establish appro-
the sample is not neutral to phenolphthalein indicator. Take
priate safety and health practices and determine the applica-
care to exclude carbon dioxide, which titrates as an acid and
bility of regulatory limitations prior to use.
gives erroneous results.
NOTE 1—There is no known ISO equivalent to this standard.
5. Significance and Use
5.1 These test methods are suitable for quality control, as
2. Referenced Documents
specification tests, and for research.
2.1 ASTM Standards:
5.2 Side reactions that form unsaturated compounds in
D883 Terminology Relating to Plastics
polypropylene oxides produce small amounts of polymers with
E180 Practice for Determining the Precision of ASTM
only one hydroxyl group per chain. These unsaturated poly-
mers lower functionality and molecular weight, while broad-
ening the overall molecular-weight distribution.
These test methods are under the jurisdiction of ASTM Committee D20 on
Plastics and are the direct responsibility of Subcommittee D20.22 on Cellular
Materials - Plastics and Elastomers. Test MethodAwas recommended toASTM by
6. Interferences
the Society of the Plastics Industry Polyurethane Raw Materials Analysis Commit-
6.1 These test methods do not apply to compounds in which
tee.
Current edition approved July 1, 2010. Published October 2010. Originally
the unsaturation is conjugated with carbonyl, carboxyl, or
approved in 1987. Last previous edition approved in 2005 as D4671 - 05. DOI:
10.1520/D4671-05R10E01.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or The last approved version of this historical standard is referenced on
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM www.astm.org.
Standards volume information, refer to the standard’s Document Summary page on Sigia, S. and Hanna, J.G., “Quantitative Organic Analysis via Functional
the ASTM website. Groups,” John Wiley and Sons, New York, 1979.
*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
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D4671 − 05(2010)
nitrile groups. Because water presumably hydrolyzes the reac- the flasks for the blank determination. Into each of the other
tion products to form basic mercuric salts, quantitative results flasks, introduce 30 g of the sample weighed to the nearest 0.1
are obtained only when the system is essentially anhydrous. g and swirl to effect complete solution. Allow the samples to
Acetone in low concentrations does not interfere significantly, stand together with the blanks at room temperature for 30 min.
although its presence can be detrimental to the end point. Swirl the flasks occasionally.Add 8 to 10 g of NaBr crystals to
Inorganic salts, especially halides, must be absent from the each flask and swirl to mix thoroughly. Add approximately 1
sample because even small amounts of salts can nullify the mL of phenolphthalein indicator solution and titrate immedi-
reaction of the mercuric acetate with the unsaturated com- ately with 0.1 N alcoholic KOH solution to a pink end point
pound. that persists for at least 15 s. Record the volume of titrant used
for the samples as D and that used for the blank as E. The
TEST METHOD A—HIGH-VOLUME REAGENT
sample titration must not exceed 50 mL of 0.1 N alcoholic
METHOD
KOH solution.
7. Apparatus
10. Calculation
7.1 Pipet, 50-mL capacity.
10.1 Calculate the acidity, meq/g, of the sample as follows:
7.2 Erlenmeyer Flask, 250-mL glass-stoppered.
C 5 ~A 3 N!/W (1)
7.3 Balance, 1000-g capacity, 0.1-g sensitivity.
where:
7.4 Buret, 50-mL capacity.
A = 0.1 N alcoholic KOH solution required to neutralize
the sample, mL,
8. Reagents
N = normality of the alcoholic KOH solution, and
8.1 Purity of Reagents—Use reagent-grade chemicals in all
W = sample used, g.
tests.Unlessotherwiseindicated,itisintendedthatallreagents
10.2 Calculate the unsaturation, meq/g, of the sample as
shall conform to the specifications of the Committee on
follows:
Analytical Reagents of theAmerican Chemical Society, where
such specifications are available. Other grades are acceptable,
Total unsaturation 5 @ D 2 E N/W# 2 C (2)
~ !
provided it is first ascertained that the reagent is of sufficiently
where:
high purity to permit its use without lessening the accuracy of
D = alcoholic KOH solution required for titration of the
the determination.
sample, mL
8.2 Mercuric Acetate, Methanol Solution (40 g/L)—
E = alcoholic KOH solution required for titration of the
Dissolve 40 g of mercuric acetate (Hg(C H O ) in sufficient
2 3 2 2
blank, average mL, and
methanol to make 1 L of solution and add sufficient glacial
C = average of results from Eq 1, meq of acidity/g of
acetic acid to require a blank titration of 1 to 10 mL of 0.1 N
sample.
alcoholicKOHsolution/50mLofreagent.Usually3or4drops
of acid are sufficient. Prepare the reagent fresh weekly and
11. Precision and Bias
filter before using.
11.1 Precision—Attempts to develop a precision and bias
8.3 Sodium Bromide (NaBr).
statement for this test method have not been successful. For
this reason, data on precision and bias cannot be given.
9. Procedure
Because this test method does not contain a numerical preci-
9.1 Add 50 mL of methanol to a sufficient number of
sion and bias statement, it shall not be used as a referee test
250-mL Erlenmeyer flasks to determine the acidity of each
method in case of dispute.Anyone wishing to participate in the
sample in duplicate. Neutralize to a faint pink end point, using
development of precision and bias data can contact the
a few drops of phenolphthalein indicator solution and 0.1 N
Chairman,SubcommitteeD20.22(SectionD20.22.01),ASTM,
alcoholicKOHsolution.Add30gofthesampleweighedtothe
100 Barr Harbor Dr., PO Box C700, West Conshohocken, PA
nearest0.1gtoeachflaskandswirltoeffectcompletesolution.
19428.
Titrate with 0.1 N alcoholic KOH solution to a pink end point
11.1.1 It is estimated that duplicate results by the same
that persists for at least 15 s and record the volume of titrant as
analyst can be considered suspect if they differ by more than
A.
0.002.
9.2 Pipet 50 mLof the Hg(C H O ) solution into each of a
2 3 2 2
11.2 Bias—The bias for this test method has not yet been
sufficient number of 250-mL Erlenmeyer flasks to make all
determined.
blank and sample determinations in duplicate. Reserve two of
TEST METHOD B—LOW-VOLUME REAGENT
Reagent Chemicals, American Chemical Society Specifications, American
METHOD
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by
...
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