ASTM D6979-24

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Designation: D6979 − 18 D6979 − 24
Standard Test Method for
Polyurethane Raw Materials: Determination of Basicity in
Polyols, Expressed as Percent Nitrogen
This standard is issued under the fixed designation D6979; 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 basic constituents in polyols that are soluble in glacial acetic acid and reactive with perchloric
acid. Samples containing 0.3 –0.3 % to 10 % nitrogen have been evaluated by this method. This test method is applicable to
polyether polyols and polyether polyol blends that are used in urethane reactions. (See Note 1.)
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
NOTE 1—This standard is equivalent to ISO 25761:08.
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
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
(Withdrawn 2009)
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
2.2 ISO Standards:
ISO 25761 Plastics—Polyols for use in the production of polyurethanes—Determination of basicity (total amine value),
expressed as percent nitrogen
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics
and Elastomers.
Current edition approved Aug. 1, 2018Feb. 1, 2024. Published August 2018February 2024. Originally approved in 2003. Last previous edition approved in 20132018 as
D6979 - 13.D6979 – 18. DOI: 10.1520/D6979-18.10.1520/D6979-24.
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.
The last approved version of this historical standard is referenced on www.astm.org.
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
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D6979 − 24
3. Terminology
3.1 Definitions—For definitions of terms Terms used in this test method see 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.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 percent nitrogen—nitrogen, n—the quantity of perchloric acid-titratable base, expressed as a weight percentage of nitrogen
in a sample.
4. Summary of Test Method
4.1 The sample is dissolved in glacial acetic acid. The resulting single-phase solution is titrated at room temperature to a
potentiometric end point with a standardized solution of perchloric acid in acetic acid. Results are reported as percent nitrogen.
5. Significance and Use
5.1 This test method is suitable for quality control, as a specification test, and for research. The results are measures of
batch-to-batch uniformity and are useful in estimating reactivity.
5.1.1 The percent nitrogen can be used to characterize a polyol or indicate amounts of certain components in a polyol blend.
5.1.2 It is permissible to also express the results in equivalents of base per gram of sample, if desired.
6. Apparatus
6.1 Potentiometric Automatic Titrator
6.2 Autotitrator Buret with Dosing Device, 20-mL
6.3 pH Glass Electrode and Reference Electrode or a Combination Glass Electrode
6.4 Analytical Balances, capable of weighing to the nearest 0.01g0.01 g and 0.0001 g
6.5 Magnetic Stirrer/Hotplate
7. Reagents and Materials
7.1 Purity of Reagents—Use reagent-grade chemicals in all tests. Unless otherwise indicated, it is intended that all reagents
conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. It is permissible to use other grades provided it is first ascertained that the reagent is of sufficiently
high purity to permit its use without lessening the accuracy of the determination.
7.2 Acetic Acid, Glacial
7.3 Acetic Anhydride
7.4 Perchloric Acid, (70 % nominal)
Reagent Chemicals, American Chemical Society Specifications, ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference
Materials, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for
Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC),
Rockville, MD.
D6979 − 24
7.5 Perchloric acid in Acetic Acid (0.10 N)—Prepare 0.10 N perchloric acid in acetic acid. For example, in a 1000-mL volumetric
flask dissolve 8.7 mL of perchloric acid in 500 mL of glacial acetic acid; add 25 mL of acetic anhydride and dilute to volume with
glacial acetic acid.
NOTE 2—Perchloric Acid—is extremely irritating to the skin, eyes and mucous membrane; highly toxic via oral and inhalation routes; and can form
explosive mixtures when mixed with carbonaceous material or allowed to dry. Concentrated material shall only be used in a hood approved for perchloric
acid use. Skin contact—wash with soap and water. Eye contact—flush with copious amounts of water for 15 minutes. Inhalation - move victim to an
uncontaminated area. Ingestion—do not induce vomiting. For all exposures seek professional medical advice.Consult the material Safety Data Sheet
(SDS) for further safety information.
8. Procedure
8.1 Weigh the appropriate amount of sample, W’ into a suitable container. Calculate the target weight of sample to be analyzed
as follows:
W’5 2/P (1
...