ASTM D4875-24

Standard Test Methods of Polyurethane Raw Materials: Determination of the Polymerized Ethylene Oxide Content of Polyether Polyols

SIGNIFICANCE AND USE
5.1 Measurements of EO content correlate to polyol reactivity (as related to primary hydroxyl content), linearity of foam rise, and hydrophilicity of the polyol and final product.
SCOPE
1.1 Test Method A—Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR) measures polymerized ethylene oxide (EO) content of ethylene oxide (EO) propylene oxide (PO) polyether polyols used in flexible polyurethane foams and non-foams. It is suitable for diols initiated from glycols of EO or PO containing EO percentages >5. For triols initiated with glycerol (glycerin) and trimethylolpropane, an uncorrected EO value is obtained since both initiators have protons that contribute to the EO measurement.  
1.2 Test Method B—Carbon-13 Nuclear Magnetic Resonance Spectroscopy (13C NMR) measures the polymerized EO content of EO-PO polyether polyols used in flexible polyurethane foams and non-foams. It is suitable for diols and triols made from the commonly used initiators and containing EO percentages >5.  
1.3 The values stated in SI units are to be regarded as standard.  
1.4 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: There is no known ISO equivalent to this standard.  
1.5 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.

General Information

• Status: Published
• Publication Date: 31-Jan-2024
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Replaces: ASTM D4875-18 - Standard Test Methods of Polyurethane Raw Materials: Determination of the Polymerized Ethylene Oxide Content of Polyether Polyols
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023
• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM E456-13a(2022) - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022

Overview

ASTM D4875-24 is the internationally recognized standard from ASTM for determining the polymerized ethylene oxide (EO) content in polyether polyols, a key raw material in polyurethane production. The EO content of polyether polyols significantly affects reactivity, foam rise profiles, and hydrophilicity, directly impacting the performance and formulation of flexible polyurethane foams and related products.

This standard outlines two test methods using Nuclear Magnetic Resonance (NMR) spectroscopy:

• Test Method A: Proton NMR (1H NMR)
• Test Method B: Carbon-13 NMR (13C NMR)

Both methods provide precise means to measure the EO content in polyols, enabling manufacturers and laboratories to ensure quality, optimize formulations, and meet performance criteria.

Key Topics

• Significance of EO Content: The EO concentration in polyether polyols influences critical characteristics such as primary hydroxyl content, foam linearity, and hydrophilicity. Accurate measurements support tailored foam properties and product consistency.
• Test Method A - 1H NMR: Applies to EO/PO polyether polyols, especially diols with EO >5%. For triols initiated by glycerin or trimethylolpropane, results are uncorrected due to initiator interference.
• Test Method B - 13C NMR: Suitable for both diols and triols from common initiators with EO >5%. Provides reliable EO content values irrespective of the polyol initiator.
• Laboratory Best Practices: Both methods require high-resolution FT-NMR equipment, careful sample preparation, and consideration of safety protocols around strong magnetic fields.
• Result Reporting and Precision: Results are reported to two decimal places, with guidance on repeatability and reproducibility based on multi-laboratory data.

Applications

ASTM D4875-24 plays a vital role in the quality control and research environments of the polyurethane industry. Key uses include:

• Quality Control for Polyurethane Raw Materials: Ensures polyol batches meet specifications for EO content, critical for process stability in foam and elastomer manufacturing.
• Product Development and Technical Service: Supports the formulation of polyether polyols with target reactivities and performance attributes for diverse end-uses, including rigid and flexible foams, adhesives, sealants, and coatings.
• Regulatory and Compliance Documentation: Provides standardized, reproducible data for compliance with industry and customer requirements.
• Interlaboratory Consistency: Enables uniformity and comparability of results across manufacturers, contract labs, and geographies, supporting global trade in polyurethane chemicals.

Related Standards

ASTM D4875-24 references several key ASTM standards that broaden its framework and application:

• ASTM D883: Terminology Relating to Plastics
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ASTM E2977: Practice for Measuring and Reporting Performance of FT-NMR Spectrometers (Liquids)
• ASTM E456: Terminology Relating to Quality and Statistics
• ASTM E2935: Practice for Evaluating Equivalence of Two Testing Processes

As of publication, there is no ISO equivalent for this standard, making ASTM D4875-24 the principal reference for EO content determination in polyether polyols on a global scale.

---

Keywords: ASTM D4875-24, polyether polyols, ethylene oxide content, NMR spectroscopy, polyurethane raw materials, quality control, flexible polyurethane foam, EO/PO ratio, test methods, industry standards, polyol reactivity, hydrophilicity, laboratory precision.

Standards Content (Sample)

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: D4875 − 24
Standard Test Methods of
Polyurethane Raw Materials: Determination of the
Polymerized Ethylene Oxide Content of Polyether Polyols
This standard is issued under the fixed designation D4875; 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* 2. Referenced Documents
1.1 Test Method A—Proton Nuclear Magnetic Resonance 2.1 ASTM Standards:
Spectroscopy ( H NMR) measures polymerized ethylene oxide D883 Terminology Relating to Plastics
(EO) content of ethylene oxide (EO) propylene oxide (PO) E691 Practice for Conducting an Interlaboratory Study to
polyether polyols used in flexible polyurethane foams and Determine the Precision of a Test Method
non-foams. It is suitable for diols initiated from glycols of EO E2977 Practice for Measuring and Reporting Performance of
or PO containing EO percentages >5. For triols initiated with Fourier-Transform Nuclear Magnetic Resonance (FT-
glycerol (glycerin) and trimethylolpropane, an uncorrected EO NMR) Spectrometers for Liquid Samples
value is obtained since both initiators have protons that E456 Terminology Relating to Quality and Statistics
contribute to the EO measurement. E2935 Practice for Evaluating Equivalence of Two Testing
Processes
1.2 Test Method B—Carbon-13 Nuclear Magnetic Reso-
nance Spectroscopy ( C NMR) measures the polymerized EO
3. Terminology
content of EO-PO polyether polyols used in flexible polyure-
3.1 Definitions—Terms used in this standard are defined in
thane foams and non-foams. It is suitable for diols and triols
accordance with Terminology D883 and Practice E2977, unless
made from the commonly used initiators and containing EO
otherwise specified. For terms relating to precision and bias
percentages >5.
and associated issues, the terms used in this standard are
1.3 The values stated in SI units are to be regarded as
defined in the accordance with Terminology E456.
standard.
3.2 Definitions of Terms Specific to This Standard:
1.4 This standard does not purport to address all of the
3.2.1 heteric polyol, n—a polyether polyol in which ethyl-
safety concerns, if any, associated with its use. It is the
ene oxide and propylene oxide units are randomly arranged.
responsibility of the user of this standard to establish appro-
3.2.2 initiator, n—a substance with which ethylene oxide or
priate safety, health, and environmental practices and deter-
propylene oxide reacts to form a polyether polyol.
mine the applicability of regulatory limitations prior to use.
3.2.2.1 Discussion—One initiator unit is incorporated into
NOTE 1—There is no known ISO equivalent to this standard.
each polymer or oligomer molecule.
1.5 This international standard was developed in accor-
3.2.3 EO capped polyol—a polyol that contains a terminal
dance with internationally recognized principles on standard-
block of ethylene oxide units
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 4. Summary of Test Methods
mendations issued by the World Trade Organization Technical 1
4.1 Test Method A—The H NMR spectra of polyether
Barriers to Trade (TBT) Committee.
polyols show two groups of resonance peaks. The first group
corresponds to the methyl protons of propylene oxide (PO).
The second group corresponds to the methylene and methine
These test methods are under the jurisdiction of ASTM Committee D20 on
Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular
Materials - Plastics and Elastomers. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2024. Published February 2024. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1988. Last previous edition approved in 2018 as D4875 - 18. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4875-24. the ASTM website.
*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
D4875 − 24
protons of PO and the methylene protons of EO. The EO peak longest relaxation time in the spectrum. It is acceptable to use
area is obtained by subtracting the area of the PO methyl peaks a different pulse angle/sequence delay combination provided
from the area of the methylene and methine peaks. Initiators that quantitative data acquisition is not compromised.
other than glycols of EO and PO give systematic errors (see 9.1.2 Number of Scans—Select the appropriate number to
Note 2). yield a signal to noise of >100:1 between 2 and 0.5 ppm
(usually 16 to 64).
NOTE 2—The initiator error can be estimated by calculating the
9.1.3 Sweep Width—~14 ppm.
theoretical contribution of initiator protons to the EO and PO peak areas.
9.1.4 Transmitter Frequency—~6 ppm.
This calculation is outside the scope of this method.
13 9.1.5 Acquisition Time—2 to 4 s.
4.2 Test Method B—The C NMR spectra of polyether
polyols contain multiple resonances arising from initiator, EO,
10. Calibration and Standardization
PO, EO-PO sequencing, tacticity, and end-group distribution.
10.1 This test method does not require standards. To evalu-
The EO content can be determined relative to PO and EO or,
relative to the triol initiator if present. In the former, the area of ate the test method, standards can be prepared by blending
commercially available poly(propylene oxide) and poly(ethyl-
the EO methylene carbons is ratioed to the total area of PO
methylene and methine carbons and EO methylene carbons. In ene oxide) diols. The molecular weights of the diols should
the latter, the area of the EO methylene carbons is ratioed to the ideally be 300 or more since lower molecular weight polyols
area of two initiator carbons. This test method describes the can contain structural configurations that are not typical of
determination of EO relative to PO and EO only. polyether polyols used in flexible polyurethane foams and
non-foams.
5. Significance and Use
11. Procedure
5.1 Measurements of EO content correlate to polyol reac-
tivity (as related to primary hydroxyl content), linearity of
11.1 Prepare a solution of the polyol in deuterated chloro-
foam rise, and hydrophilicity of the polyol and final product.
form. A 0.5-5 % solution is recommended. Add one to two
drops of trifluoroacetic acid and mix well. More acid will be
TEST METHOD A—PROTON NMR
required if a higher than recommended concentration of polyol
is used (see NOTE 3).
6. Apparatus
11.2 Transfer an appropriate amount of the sample solution
6.1 Fourier Transform NMR (FT-NMR) Spectrometer, with
to an NMR tube.
a proton resonance frequency of 200 MHz or higher. The
spectrometer is to have a minimum proton signal-to-noise ratio
11.3 Place the NMR tube into a spinner, adjust it to the
of 100:1 based on a 0.1 % ethylbenzene in deuterated chloro-
appropriate depth and insert it into the spectrometer probe.
form (CDCl ) sample that has been pulsed once using a 90°
11.4 Obtain a stable lock on the solvent.
pulse angle under the conditions described in Practice E2977.
11.5 Tune and match the probe.
6.2 NMR sample tubes, having outside diameters of 5 mm.
11.6 Shim the sample to optimize field-homogeneity.
6.3 NMR spinners.
11.7 Acquire the NMR data.
7. Reagents and Materials
11.8 Zero fill the data. The recommended value is 1 or 2 x
7.1 All reagents are to be spectroscopic grade and free of
number of points.
magnetic materials.
11.9 Apply a spectral weighting function (apodization) and
7.2 Trifluoroacetic acid.
Fourier Transform the Free Induction Decay (FID). The
recommended apodization is an exponential window multipli-
7.3 Deuterated chloroform, containing tetramethylsilane
cation and a typical line broadening value is 1/acquisition time.
(TMS) as an internal standard.
11.10 Phase and baseline correct the spectrum.
8. Hazards
11.11 Set the internal TMS reference to 0 ppm.
8.1 Magnetic Fields—Follow the manufacturer’s recom-
11.12 Expand and integrate the peaks of interest. The
mendation for the safe operation of the instrument.
methyl protons of PO typically resonate in the 0.5-1.7 ppm
8.1.1 Persons with implanted or attached medical devices
region (Area A). The methylene and methine protons of PO and
such as pacemakers and prosthetic parts must remain outside
the methylene protons of EO typically resonate in the 2.8-4.8
the 5-gauss perimeter.
ppm region (Area B). An example is shown in Fig. 1 (see Note
8.1.2 Objects made of ferromagnetic material will be at-
4).
tracted to the magnet and are to be kept a safe distance away.
NOTE 3—Trifluoroacetic acid is added to move hydroxyl (OH) protons
9. Preparation of Apparatus
to a higher chemical shift and away from the regions of interest. The
sample should be run as soon as practical after preparation to minimize the
9.1 Prepare a proton NMR experiment selecting appropriate
formation of esters of trifluoroacetic acid.
parameters to obtain quantitative integration of the spectrum.
NOTE 4—Allyl unsaturation, if present, will contribute to the integral
9.1.1 Pulse Angle and Sequence Delay Time—Select a 90
value of Area B. This contribution is expected to be minor for typical
degree pulse angle with a delay of 10 × T of the peak with the EO-PO polyether polyols and can be corrected by subtracting the integral
D4875 − 24
FIG. 1 H NMR Spectrum of a DPG Initiated EO/PO Polyol (BB23798)
value of two ally protons that have chemical shifts outside the regions of
generate data specific to their materials and laboratory (or
interest. This correction is not included in the scope of this method.
between specific laboratories). The principles would then be
valid for such data.
12. Calculation
14.3 Repeatability, (r)—It has been determined that the
12.1 Calculate the weight percent EO content using the
maximum expected difference between two test results for the
following equation:
same material, obtained by the same operator using the
~C*44.05!
equipment on the same day in the same laboratory due solely
EO, wt. % 5 *100 (1)
C * 44.05 1 D * 58.08
~ ! ~ !
to the method is r.
where:
14.4 Reproducibility, (R)—It has been estimated that the
A = area of methyl PO protons, maximum expected difference between two test results for the
B = area of methylene and methine PO protons and area
same material, obtained by different operators using different
of methylene EO protons,
equipment in different laboratories due solely to the method is
C = (B – A) ⁄4 integral per EO proton,
R.
D = A/3 integral per PO proton,
14.5 Any judgment in accordance with the repeatability
44.05 = g EO/mole, and
(14.3) and reproducibility (14.4) would have an approximate
58.08 = g PO/mole.
95 % (0.95) probability of being correct.
13. Report
14.6 Bias—There are no recognized standards by which to
13.1 Report the % EO content to two decimal places. For
estimate bias of this method.
polyether polyols with initiators other than glycols of EO and
14.7 For information on equivalence, refer to Practice
PO, report that the value is uncorrected for the initiator.
E2935.
14. Precision and Bias
TEST METHOD B—CARBON-13 NMR
14.1 Table 1 is based on a round robin conducted in 2016 in
accordance with Practice E691, involving five materials tested
15. Apparatus
by six laboratories. For each material, all the samples were
15.1 High Resolution Fourier-Transform NMR
prepared at one source, but the individual specimens were
Spectrometer, with carbon-13 capability, and a carbon-13
prepared at the laboratories which tested them. Each test result
resonance f
...

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: D4875 − 18 D4875 − 24
Standard Test Methods of
Polyurethane Raw Materials: Determination of the
Polymerized Ethylene Oxide Content of Polyether Polyols
This standard is issued under the fixed designation D4875; 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 Test Method A—Proton Nuclear Magnetic Resonance Spectroscopy ( H NMR) measures polymerized ethylene oxide (EO)
content of ethylene oxide (EO) propylene oxide (PO) polyether polyols used in flexible polyurethane foams and non-foams. It is
suitable for diols initiated from glycols of EO or PO containing EO percentages >5. For triols initiated with glycerol (glycerin)
and trimethylolpropane, an uncorrected EO value is obtained since both initiators have protons that contribute to the EO
measurement.
1.2 Test Method B—Carbon-13 Nuclear Magnetic Resonance Spectroscopy ( C NMR) measures the polymerized EO content of
EO-PO polyether polyols used in flexible polyurethane foams and non-foams. It is suitable for diols and triols made from the
commonly used initiators and containing EO percentages >5.
1.3 The values stated in SI units are to be regarded as standard.
1.4 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—There is no known ISO equivalent to this standard.
1.5 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
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2977 Practice for Measuring and Reporting Performance of Fourier-Transform Nuclear Magnetic Resonance (FT-NMR)
Spectrometers for Liquid Samples
E456 Terminology Relating to Quality and Statistics
E2935 Practice for Evaluating Equivalence of Two Testing Processes
These test methods are 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 April 1, 2018Feb. 1, 2024. Published April 2018February 2024. Originally approved in 1988. Last previous edition approved in 20112018 as
D4875 - 11.D4875 - 18. DOI: 10.1520/D4875-18.10.1520/D4875-24.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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
D4875 − 24
3. Terminology
3.1 Definitions—For definitions of terms that appear in this method refer to Terms used in this standard are defined in accordance
with Terminology D883 and Practice E2977, unless otherwise specified. For terms relating to precision and bias and associated
issues, the terms used in this standard are defined in the accordance with Terminology E456.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 heteric polyol, n—a polyether polyol in which ethylene oxide and propylene oxide units are randomly arranged.
3.2.2 initiator, n—a substance with which ethylene oxide or propylene oxide reacts to form a polyether polyol.
3.2.2.1 Discussion—
One initiator unit is incorporated into each polymer or oligomer molecule.
3.2.3 EO capped polyol—a polyol that contains a terminal block of ethylene oxide units
4. Summary of Test Methods
4.1 Test Method A—The H NMR spectra of polyether polyols show two groups of resonance peaks. The first group corresponds
to the methyl protons of propylene oxide (PO). The second group corresponds to the methylene and methine protons of PO and
the methylene protons of EO. The EO peak area is obtained by subtracting the area of the PO methyl peaks from the area of the
methylene and methine peaks. Initiators other than glycols of EO and PO give systematic errors (see Note 2).
NOTE 2—The initiator error can be estimated by calculating the theoretical contribution of initiator protons to the EO and PO peak areas. This calculation
is outside the scope of this method.
4.2 Test Method B—The C NMR spectra of polyether polyols contain multiple resonances arising from initiator, EO, PO, EO-PO
sequencing, tacticity, and end-group distribution. The EO content can be determined relative to PO and EO or, relative to the triol
initiator if present. In the former, the area of the EO methylene carbons is ratioed to the total area of PO methylene and methine
carbons and EO methylene carbons. In the latter, the area of the EO methylene carbons is ratioed to the area of two initiator
carbons. This test method describes the determination of EO relative to PO and EO only.
5. Significance and Use
5.1 Measurements of EO content correlate to polyol reactivity (as related to primary hydroxyl content), linearity of foam rise, and
hydrophilicity of the polyol and final product.
TEST METHOD A—PROTON NMR
6. Apparatus
6.1 Fourier Transform NMR (FT-NMR) Spectrometer, with a proton resonance frequency of 200 MHz or higher. The spectrometer
is to have a minimum proton signal-to-noise ratio of 100:1 based on a 0.1 % ethylbenzene in deuterated chloroform (CDCl )
sample that has been pulsed once using a 90° pulse angle under the conditions described in Practice E2977.
6.2 NMR sample tubes, having outside diameters of 5 mm.
6.3 NMR spinners.
7. Reagents and Materials
7.1 All reagents are to be spectroscopic grade and free of magnetic materials.
7.2 Trifluoroacetic acid.
7.3 Deuterated chloroform, containing tetramethylsilane (TMS) as an internal standard.
D4875 − 24
8. Hazards
8.1 Magnetic Fields—Follow the manufacturer’s recommendation for the safe operation of the instrument.
8.1.1 Persons with implanted or attached medical devices such as pacemakers and prosthetic parts must remain outside the 5-gauss
perimeter.
8.1.2 Objects made of ferromagnetic material will be attracted to the magnet and are to be kept a safe distance away.
9. Preparation of Apparatus
9.1 Prepare a proton NMR experiment selecting appropriate parameters to obtain quantitative integration of the spectrum.
9.1.1 Pulse Angle and Sequence Delay Time—Select a 90 degree pulse angle with a delay of 10 × T of the peak with the longest
relaxation time in the spectrum. It is acceptable to use a different pulse angle/sequence delay combination provided that
quantitative data acquisition is not compromised.
9.1.2 Number of Scans—Select the appropriate number to yield a signal to noise of >100:1 between 2 and 0.5 ppm (usually 16
to 64).
9.1.3 Sweep Width—~14 ppm.
9.1.4 Transmitter Frequency—~6 ppm.
9.1.5 Acquisition Time—2 to 4 s.
10. Calibration and Standardization
10.1 This test method does not require standards. To evaluate the test method, standards can be prepared by blending commercially
available poly(propylene oxide) and poly(ethylene oxide) diols. The molecular weights of the diols should ideally be 300 or more
since lower molecular weight polyols can contain structural configurations that are not typical of polyether polyols used in flexible
polyurethane foams and non-foams.
11. Procedure
11.1 Prepare a solution of the polyol in deuterated chloroform. A 0.5-5 % solution is recommended. Add one to two drops of
trifluoroacetic acid and mix well. More acid will be required if a higher than recommended concentration of polyol is used (see
NOTE 3).
11.2 Transfer an appropriate amount of the sample solution to an NMR tube.
11.3 Place the NMR tube into a spinner, adjust it to the appropriate depth and insert it into the spectrometer probe.
11.4 Obtain a stable lock on the solvent.
11.5 Tune and match the probe.
11.6 Shim the sample to optimize field-homogeneity.
11.7 Acquire the NMR data.
11.8 Zero fill the data. The recommended value is 1 or 2 x number of points.
11.9 Apply a spectral weighting function (apodization) and Fourier Transform the Free Induction Decay (FID). The recommended
apodization is an exponential window multiplication and a typical line broadening value is 1/acquisition time.
D4875 − 24
FIG. 1 H NMR Spectrum of a DPG Initiated EO/PO Polyol (BB23798)
11.10 Phase and baseline correct the spectrum.
11.11 Set the internal TMS reference to 0 ppm.
11.12 Expand and integrate the peaks of interest. The methyl protons of PO typically resonate in the 0.5-1.7 ppm region (Area
A). The methylene and methine protons of PO and the methylene protons of EO typically resonate in the 2.8-4.8 ppm region (Area
B). An example is shown in Fig. 1 (see Note 4).
NOTE 3—Trifluoroacetic acid is added to move hydroxyl (OH) protons to a higher chemical shift and away from the regions of interest. The sample should
be run as soon as practical after preparation to minimize the formation of esters of trifluoroacetic acid.
NOTE 4—Allyl unsaturation, if present, will contribute to the integral value of Area B. This contribution is expected to be minor for typical EO-PO
polyether polyols and can be corrected by subtracting the integral value of two ally protons that have chemical shifts outside the regions of interest. This
correction is not included in the scope of this method.
D4875 − 24
TABLE 1 Polymerized Ethylene Oxide Content of Polyether Polyols by Proton NMR
B C D E
Sample Material OH Value Mean S S r R
r R
(mg KOH/g)
BB23794 Glycerol/EO-PO 43 74.79 0.14 0.31 0.38 0.85
(EO+PO > 6.5)
mixed feed
BB23796 EO/PO 30 16.62 0.11 0.53 0.31 1.49
BB23797 Blend of PPG 69 4.95 0.17 0.63 0.49 1.75
2000 and PEG
A
BB23798 DPG/EO-PO 30 26.51 0.10 0.48 0.27 1.34
(EO+PO > 4.5)
BB23799 DPG/EO-PO 31 20.30 0.07 0.50 0.19 1.40
(EO+PO > 4.5)
A
Phase separation was observed in sample BB23797. The data for this sample are expected to include this variability.
B
S = within laboratory standard deviation for the indicated material. It is obtained by pooling the within-laboratory standard deviations of the test results from all of the
r
participating laboratories:
2 2 2 1/2
S = [ [ (S ) + (S ) + { { (S ) ]/n] where n = number of participating laboratories.
r 1 2 n
C
S = between-laboratories reproducibility, expressed as standard deviation:
R
2 2 1/2
S = [S + S ] where S = standard deviation of laboratory means.
R r L L
D
r = within-laboratory critical interval between two test results = 2.8 × S .
r
E
R = between-laboratories critical interval between two test results = 2.8 × S .
R
12. Calculation
12.1 Calculate the weight percent EO content using the following equation:
C*44.05*100
EO,wt%5 ×100 (1)
C * 44.05 1 D * 58.08
~ ! ~ !
~C*44.05!
EO,wt.%5 *100 (1)
C * 44.05 1 D * 58.08
~ ! ~ !
where:
A = area of methyl PO protons,
B = area of methylene and methine PO protons and area of methylene EO protons,
C = (B–A)/4 integral per EO proton,
C = (B – A) ⁄4 integral per EO proton,
D = A/3 integral per PO proton,
44.05 = g EO/mole, and
58.08 = g PO/mole.
13. Report
13.1 Report the % EO content to two decimal places. For polyether polyols with initiators other than glycols of EO and PO, report
that the value is uncorrected for the initiator.
14. Precision and Bias
14.1 Table 1 is based on a round robin conducted in 2016 in accordance with Practice E691, involving five materials tested by
six laboratories. For each material, all the samples were prepared at one source, but the individual specimens were prepared at the
laboratories which tested them. Each test result was a single determination. Each laboratory obtained two test results for each
material.
14.2 Caution—The explanation of “r” and “R” is only intended to present a meaningful way of considering the approximate
precision of this test method. Do not apply the data in Table 1 to accept or reject materials, as these data apply only to the materials
tested in the round robin and are unlikely to be
...