1、Designation: D4273 11D4273 18Standard Test Method forPolyurethane Raw Materials: Determination of PrimaryHydroxyl Content of Polyether Polyols1This standard is issued under the fixed designation D4273; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 Carbon-13 Nuclear Magnetic Resonance Spectroscopy (carbon-13(13 NMR),C NMR) measures t
3、he primary hydroxylcontent of ethylene oxide-propylene oxide polyethers oxide (EO)-propylene oxide (PO) polyether polyols used in preparingflexible polyurethane foams. It This method is best suited for polyethers polyether polyols with primary hydroxyl contents of 10to 90 %.1.2 The values stated in
4、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 responsibilityof the user of this standard to establish appropriate safety safety,
5、 health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.NOTE 1There is no known ISO equivalent to this standard.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablishe
6、d in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsE180 Practice for Determining t
7、he Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals(Withdrawn 2009)3E386 Practice for Data Presentation Relating to High-Resolution Nuclear Magnetic Resonance (NMR) Spectroscopy(Withdrawn 2015)3E691 Practice for Conducting an Interlaboratory Study to Determine
8、 the Precision of a Test MethodE2977 Practice for Measuring and Reporting Performance of Fourier-Transform Nuclear Magnetic Resonance (FT-NMR)Spectrometers for Liquid Samples3. Terminology3.1 DefinitionsThe terminology in this test method follows the standard terminology defined in Practice For defi
9、nitions ofterms that appear in this method, refer to Terminology E386D883 and in Terminology Practice D883E2977.4. Summary of Test Method4.1 The resonance peaks Peaks of the primary and secondary hydroxyl carbons of the polyetherspolyether polyols used inflexible urethanepolyurethane foams are well-
10、resolved in high-resolution 13carbon-13C NMR spectra.The peak areas are measuredby the spectrometers integration system, and the relative primary hydroxyl content is determined from the ratio of the primaryhydroxyl area to the total area of the primary and secondary hydroxyl resonance peaks.hydroxyl
11、 (primary and secondary) area.1 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 - Plasticsand Elastomers.Current edition approved April 1, 2011April 1, 2018. Published April 2011April 2018. Ori
12、ginally approved in 1983. Last previous edition approved in 20052011 asD4273 - 05.D4273 - 11. DOI: 10.1520/D4273-11.10.1520/D4273-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume inform
13、ation, refer to the standards Document Summary page on the ASTM website.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. Becauseit may not be technically possible to adequately dep
14、ict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM Internatio
15、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 Measurements of The primary hydroxyl content are useful for providing information regardingprovides information aboutthe relative reactivities of polyols.6. Interferences6.1 Any primar
16、y hydroxyl propoxylate carbons present Primary hydroxyl PO methylene carbons (where the methylene carbonis next to the hydroxyl group and the methine carbon is next to the ether oxygen) are integrated with the secondary hydroxylcarbons and are therefore not included in the primary hydroxyl content a
17、s measured by this method.7. Equipment7.1 Pulse Fourier-Transform NMR (FT-NMR) Spectrometer, with carbon-13 capability and a carbon-13 resonance frequency of15 MHz (proton resonance frequency of 60 MHz) or higher. The spectrometer is to have a minimum signal-to-noise ratio of 70:1,based on the large
18、st aromatic peak of 90 % ethylbenzene sample that has been pulsed one time using a 90 pulse.7.2 NMR Sample Tubes, with outer diameters of 5 mm or more.7. Apparatus7.1 Fourier-Transform NMR (FT-NMR) Spectrometer, with carbon-13 capability and a carbon-13 resonance frequency of 50MHz (proton resonance
19、 frequency of 200 MHz) or higher. The spectrometer is to have a minimum carbon-13 signal-to-noise ratioof 70:1 based on the benzene carbon signal in a 60 % benzene-d6, 40 % p-dioxane (v/v) sample (ASTM NMR standard) that hasbeen pulsed once using a 90 pulse angle under the conditions specified in Pr
20、actice E2977.7.2 NMR sample tubes having outside diameters of 5 mm or more.7.3 NMR spinners.8. Reagents and Materials8.1 All reagents are to be NMR-grade, deuterated solvents.8.1 Deuterated Chloroform or Deuterated Acetone, containing tetramethylsilane (TMS) as an internal standard.All reagents aret
21、o be spectroscopic-grade and free of magnetic materials.8.1.1 Deuterated chloroform or deuterated acetone, containing tetramethylsilane (TMS) as an internal standard.9. Standards9.1 This test method does not require standards. To evaluate the test method, standards can be prepared by mixing in solut
22、ioncommercially available poly(propylene oxide) and poly(ethylene oxide) diols. The molecular weight of the standard would ideallybe 300 or more since lower-molecular-weight polyols can contain structural configurations that are not typical of polyethers usedin flexible urethane foams.9. Hazards9.1
23、Magnetic FieldsFollow the manufacturers recommendation for the safe operation of the instrument.9.1.1 Persons with implanted or attached medical devices such as pacemakers and prosthetic parts must remain outside the5-gauss perimeter.9.1.2 Objects made of ferromagnetic material will be attracted to
24、the magnet and are to be kept a safe distance away.10. Preparation of Sample10.1 Mix 3 mL of polyol with 1.5 to 2 mL of deuterated chloroform or deuterated acetone. Transfer an appropriate amount tothe NMR tube.10. Preparation of Apparatus10.1 Prepare a proton decoupled carbon-13 NMR experiment, sel
25、ecting appropriate parameters to obtain quantitative integrationof the peaks in the 68-60 ppm region.10.1.1 Inverse Gated DecouplingDecouple only during acquisition.10.1.2 Pulse Angle and Sequence Delay TimeSelect a 90 degree pulse angle with a sequence delay of 5 to 10 T1 of the peakwith the longes
26、t relaxation time in the 68-60 ppm region. It is acceptable to use a different pulse angle/sequence delay combinationto reduce acquisition time provided that quantitative data acquisition is not compromised.10.1.3 Number of ScansSelect the appropriate number to yield a minimum signal to noise of 10:
27、1 for the smallest peakintegrated over the 68-60 ppm region (usually 1024 to 2048).10.1.4 Sweep Width 220 ppm.10.1.5 Transmitter Frequency100 ppm.D4273 18210.1.6 Acquisition Time1 to 2 s.11. Instrument Preparation11.1 Prepare a decoupled carbon-13 NMR experiment, selecting appropriate parameters to
28、obtain quantitative integration of thepeaks in the 67-60 ppm region.11.2 The settings presented here are examples that apply to a Bruker WP-80 spectrometer and a Varian AC 300 spectrometer.Instrument settings for other spectrometers vary. Consult the manufacturers operating manual.11.2.1 Typical Bru
29、ker WP-80 spectrometer parameters are as follows:Nucleus observed Carbon-13Spectral width 3000 HzPulse angle 30Data points 8KAcquisition time 1.36 sDelay between pulses 0.0 s1 H decoupler Broadband11.2.2 Typical Varian AC 300 spectrometer parameters are as follows:Nucleus observed Carbon-13Spectral
30、width 100 ppmPulse angle 90Data points 32KAcquisition time 2 sPulse delay 5 s1 H decoupler on, or gated decoupling11. Calibration and Standardization11.1 This test method does not require standards. To evaluate the test method, standards can be prepared by blendingcommercially available poly(propyle
31、ne oxide) and poly(ethylene oxide) diols. The molecular weights of the diols should ideallybe 300 or more since lower molecular weight polyols can contain structural configurations that are not typical of polyether polyolsused in flexible polyurethane foams.12. NMR Analysis12.1 Place the NMR tube co
32、ntaining the sample solution into the spectrometer probe. After a stable lock is obtained, optimizethe field homogeneity. Collect a sufficient number of repetitive scans for the analysis. The number required depends on thespectrometer, the molecular weight of the polyol, and the functionality of the
33、 polyol. Some samples will require repetitive scanningfor 30 min or less, while some will require an hour or more. After scanning, transform the free induction decay (FID) to thefrequency-domain spectrum. The primary hydroxyl peaks at about 61 ppm and the secondary hydroxyl peaks at about 66 ppm are
34、then expanded, amplified, and integrated (the chemical shifts are based on TMS set at 0.0 ppm). See Figs. 1-4 for examples ofspectra obtained for two different polyols.12. Procedure12.1 Prepare a solution of the polyol sample in deuterated chloroform or deuterated acetone containing TMS as an intern
35、alstandard. A 30-60 % solution is recommended. (See Note 2.)12.2 Transfer an appropriate amount of the sample solution to an NMR tube.12.3 Place the NMR tube into a spinner, adjust it to the appropriate depth and insert it into the spectrometer probe.12.4 Obtain a stable lock on the solvent.12.5 Tun
36、e and match the probe.12.6 Shim the sample to optimize field-homogeneity.12.7 Acquire the NMR data.12.8 Zero fill the data. The recommended value is 1 or 2 number of points.12.9 Apply a spectral weighting function (apodization) and Fourier Transform the Free Induction Decay (FID). Therecommended apo
37、dization is an exponential window multiplication and a typical line broadening value is 1/acquisition time.12.10 Phase and baseline correct the spectrum.12.11 Set the internal TMS reference to 0 ppm.12.12 Expand and integrate the peaks of interest. The primary hydroxyl peaks typically resonate in th
38、e 61.0 to 62.5 ppm regionand the secondary hydroxyl peaks typically resonate in the 65.5 to 67.5 ppm region. An example is shown in Fig. 1.NOTE 2The use of 0.025 to 0.05 M Cr(acac)3 has been found to shorten relaxation times allowing for shorter data acquisition times.D4273 18313. Calculation13.1 De
39、termine the areas of the primary and secondary peaks from the integration curves. Calculate the mole Calculate thepercent primary hydroxyl from content using the following equation:Primary hydroxyl,%5 ApAp1As3100 (1)Primary hydroxyl,%5A* 100A1B (1)where:where:Ap = area of primary hydroxyl peaks, and
40、As = area of secondary hydroxyl peaks.A = area of terminal EO methylene carbons (primary hydroxyl peaks),B = area of terminal PO methine carbons (secondary hydroxyl peaksdoes not correct for primary hydroxyl PO terminations).The area of each peak type is in accordance with Fig. 1 and Fig. 2.14. Repo
41、rt14.1 Report results the % primary hydroxyl content to the nearest percent primary hydroxyl.two decimal places.15. Precision and Bias315.1 Table 1 is based on a round robin conducted in 19792016 in accordance with Practice E691, involving six polyol sampleswith primary hydroxyl contents from 11 to
42、76 % and hydroxyl numbers from 24 to 109 (five materials Table 2) tested by eightlaboratories. For each polyol,material, all of the samples were prepared at one source, but the individual specimens were preparedat the laboratories thatwhich tested them. Each test result was obtained from one individ
43、ual NMR run. a single determination. Eachlaboratory obtained two test results for each material on two separate days.material.15.2 CautionInThe Table 1, for explanation of repeatability (r) and reproducibility (Rthe polyols indicated and the test resultsthat are derived) is only intended to present
44、a meaningful way of considering the approximate precision of this test method. Donot apply the data in Table 1 to accept or reject materials, as these data apply only to the materials tested in the round robin andare unlikely to be rigorously representative of other lots, formulations, conditions, m
45、aterials, or laboratories. Users of this testmethod need to apply the principles outlined in Practice E691 from testing two specimens of each polyol on each of two separatedays:to generate data specific to their materials and laboratory (or between specific laboratories). The principles would then b
46、evalid for such data.15.2.1 Sr = within-laboratory standard deviation of the average: Ir = 2.83 Sr. (See 15.2.3 for application of Ir.)15.2.2 SR = between-laboratory standard deviation of the average: IR = 2.83 SR. (See 15.2.4 for application of IR.)3 Supporting data are available from ASTM Headquar
47、ters. Request RR:D20-1108RR:D20-1270.FIG. 1 13 Primary Hydroxyl Carbon Peaks of 3500 MW Triol (52 % Primary)C NMR Spectrum of an EO-PO Polyol (BB23796)D4273 18415.2.3 RepeatabilityIn comparing two test results for the same polyol, obtained by the same operator using the sameequipment on the same day
48、, those test results are to be judged not equivalent if they differ by more than the Ir value for that polyoland condition.15.2.4 ReproducibilityIn comparing two test results for the same polyol, obtained by different operators using differentequipment on different days, those test results are to be
49、 judged not equivalent if they differ by more than the IR value for that polyoland condition. (This applies between different laboratories or between equipment within the same laboratory.)15.2.5 Any judgement in accordance with 15.2.3 and 15.2.4 will have an approximate 95 % (0.95) probability of being correct.15.2.6 Other polyols can yield somewhat different results.15.3 RepeatabilityFor further information on the methodology used in this section, see Practice Precision under repeatabilityconditions.E691.15.4 ReproducibilityPrecision under reproduc
