ASTM D4672-24
(Test Method)Standard Test Method for Polyurethane Raw Materials: Determination of Water Content of Polyols
Standard Test Method for Polyurethane Raw Materials: Determination of Water Content of Polyols
SIGNIFICANCE AND USE
5.1 This test method is suitable for quality control, as a specification test, and for research. The water content of a polyol is important since isocyanates react with water.
SCOPE
1.1 This test method measures the water content of polyols and many other organic compounds.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1: This test method is equivalent to ISO 14897.
1.4 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.
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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: D4672 − 24
Standard Test Method for
Polyurethane Raw Materials: Determination of Water
1
Content of Polyols
This standard is issued under the fixed designation D4672; 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.
3
1. Scope* 2.2 ISO Standards:
ISO 14897 Plastics—Polyols for use in the production of
1.1 This test method measures the water content of polyols
polyurethane—Determination of water content
and many other organic compounds.
1.2 The values stated in SI units are to be regarded as the 3. Terminology
standard. The values given in parentheses are for information
3.1 Definitions—Terms used in this standard are defined in
only.
accordance with Terminology D883, unless otherwise speci-
fied. For terms relating to precision and bias and associated
1.3 This standard does not purport to address all of the
issues, the terms used in this standard are defined in accordance
safety concerns, if any, associated with its use. It is the
with Terminology E456.
responsibility of the user of this standard to establish appro-
3.1.1 polyurethane, n—a polymer prepared by the reaction
priate safety, health, and environmental practices and deter-
of an organic diisocyanate with polyols.
mine the applicability of regulatory limitations prior to use.
3.1.1.1 Discussion—Polyurethanes, or urethanes, as they are
NOTE 1—This test method is equivalent to ISO 14897.
sometimes called, can be thermosetting, thermoplastic, rigid,
flexible, cellular or solid. (See Terminology D883.)
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Summary of Test Methods
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4.1 This method is based on volumetric or coulometric
mendations issued by the World Trade Organization Technical
titrations that follow the reduction of iodine by sulfur dioxide
Barriers to Trade (TBT) Committee.
in the presence of water. An alcohol (ROH) and an amine (R'N)
react with sulfur dioxide (SO ) to form an intermediate that is
2
2. Referenced Documents
then oxidized by the stoichiometric reaction of iodine and
2
water in the presence of the amine according to the following
2.1 ASTM Standards:
reactions:
D883 Terminology Relating to Plastics
ROH + SO + R'N → [R'NH]SO R
2 3
E203 Test Method for Water Using Volumetric Karl Fischer
H O + I + [R'NH]SO R + 2R'N → [R'NH]SO R + 2[R'NH]I
2 2 3 4
Titration
E456 Terminology Relating to Quality and Statistics 4.2 Pyridine was historically used but has been displaced by
imidazole and other amines. Methanol is a commonly used
E691 Practice for Conducting an Interlaboratory Study to
alcohol, but others are available. In Karl Fischer titrations,
Determine the Precision of a Test Method
iodine is either added as part of the titrant by buret (volumetry)
E2935 Practice for Evaluating Equivalence of Two Testing
or is generated electrochemically in the titration cell (coulom-
Processes
etry). Coulometric titrations eliminate the need for standardiz-
ing the reagent.
1
4.3 This method provides details specific to water determi-
This test method is under the jurisdiction of ASTM Committee D20 on Plastics
and are the direct responsibility of Subcommittee D20.22 on Cellular Materials -
nations in polyols. A general procedure for volumetric Karl
Plastics and Elastomers.
Fischer analysis, including a list of interferences, can be found
Current edition approved Feb. 1, 2024. Published February 2024. Originally
in Test Method E203.
approved in 1991. Last previous edition approved in 2018 as D4672 - 18. DOI:
10.1520/D4672-24.
2
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
3
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
1
---------------------- Page: 1 ----------------------
D4672 − 24
5. Significance and Use 10. Procedure
5.1 This test method is suitable for quality control, as a 10.1 Refer to the operating manual for the autotitrator in
sp
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4672 − 18 D4672 − 24
Standard Test Method for
Polyurethane Raw Materials: Determination of Water
1
Content of Polyols
This standard is issued under the fixed designation D4672; 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*
1.1 This test method measures the water content of polyols and many other organic compounds.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
NOTE 1—This test method is equivalent to ISO 14897.
1.4 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D883 Terminology Relating to Plastics
E203 Test Method for Water Using Volumetric Karl Fischer Titration
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2935 Practice for Evaluating Equivalence of Two Testing Processes
3
2.2 ISO Standards:
ISO 14897 Plastics—Polyols for use in the production of polyurethane—Determination of water content
3. Terminology
3.1 Definitions:Definitions—Terms used in this standard are defined in accordance with Terminology D883, unless otherwise
specified. For terms relating to precision and bias and associated issues, the terms used in this standard are defined in accordance
with Terminology E456.
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and are the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics
and Elastomers.
Current edition approved April 1, 2018Feb. 1, 2024. Published April 2018February 2024. Originally approved in 1991. Last previous edition approved in 20122018 as
D4672 - 12.D4672 - 18. DOI: 10.1520/D4672-18.10.1520/D4672-24.
2
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 the ASTM website.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 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
1
---------------------- Page: 1 ----------------------
D4672 − 24
3.1.1 polyurethane, n—a polymer prepared by the reaction of an organic diisocyanate with compounds containing hydroxyl
groups.polyols.
3.1.1.1 Discussion—
Polyurethanes, or urethanes, as they are sometimes called, can be thermosetting, thermoplastic, rigid or soft and rigid, flexible,
cellular or solid. (See Terminology D883.)
4. Summary of Test Methods
4.1 This method is based essentially on volumetric or coulometric titrations that follow the reduction of iodine by sulfur dioxide
in the presence of water. This reaction proceeds quantitatively when methanol or another An alcohol (ROH) and pyridine (Can
H N) or a similar amine (R'N) are present to react with the sulfur trioxidedioxide (SO ) and hydriodic acid (HI) produced to form
5 5 32
an intermediate that is then oxidized by the stoichiometric reaction of iodine and water in the presence of the amine according to
the following reactions:
ROH + SO + R'N → [R'NH]SO R
2 3
H O + I + [R'NH]SO R + 2R'N → [R'NH]SO R + 2[R'NH]I
2 2 3 4
4.2 To determine water, Karl Fischer reagent (a solution of iodine, sulfur dioxide, imidazole, and pyridine or a pyridine substitute)
is added to a solution of the sample in methanol or other alcohol until all of the water present has been consumed. The titrant is
either added Pyridine was historically used
...
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