1、Designation:D427311Standard 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 case of revi
2、sion,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 NMR),measures the primary hydroxyl content of
3、ethylene oxide-propylene oxide polyethers used in preparingflexible foams.It is best suited for polyethers with primaryhydroxyl contents of 10 to 90%.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not
4、purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE1There is no known ISO equivalent to this
5、 standard.2.Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)3E386 Practice for Data Presentation Relating to High-Resolution Nuclear
6、Magnetic Resonance(NMR)Spec-troscopyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 The terminology in this test method follows the standardterminology defined in Practice E386 and in TerminologyD883.4.Summary of Test Method4.1 The res
7、onance peaks of the primary and secondaryhydroxyl carbons of the polyethers used in flexible urethanefoams are well-resolved in high-resolution carbon-13 NMRspectra.The peak areas are measured by the spectrometersintegration system,and the relative primary hydroxyl content isdetermined from the rati
8、o of the primary hydroxyl area to thetotal area of the primary and secondary hydroxyl resonancepeaks.5.Significance and Use5.1 Measurements of primary hydroxyl content are usefulfor providing information regarding the relative reactivities ofpolyols.6.Interferences6.1 Any primary hydroxyl propoxylat
9、e carbons present(where the methylene carbon is next to the hydroxyl group andthe methine carbon is next to the ether oxygen)are integratedwith the secondary hydroxyl carbons and are therefore notincluded in the primary hydroxyl content as measured by thismethod.7.Equipment7.1 Pulse Fourier-Transfor
10、m NMR(FT-NMR)Spectrometer,with carbon-13 capability and a carbon-13 resonance fre-quency of 15 MHz(proton resonance frequency of 60 MHz)orhigher.The spectrometer is to have a minimum signal-to-noiseratio of 70:1,based on the largest aromatic peak of 90%ethylbenzene sample that has been pulsed one ti
11、me using a 90pulse.7.2 NMR Sample Tubes,with outer diameters of 5 mm ormore.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials-Plastics and Elastomers.Current edition approved April 1,2011.Publish
12、ed April 2011.Originallyapproved in 1983.Last previous edition approved in 2005 as D4273-05.DOI:10.1520/D4273-11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the stan
13、dards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United St
14、ates1 8.Reagents8.1 All reagents are to be NMR-grade,deuterated solvents.8.2 Deuterated Chloroform or Deuterated Acetone,contain-ing tetramethylsilane(TMS)as an internal standard.9.Standards9.1 This test method does not require standards.To evaluatethe test method,standards can be prepared by mixing
15、 insolution commercially available poly(propylene oxide)andpoly(ethylene oxide)diols.The molecular weight of thestandard would ideally be 300 or more since lower-molecular-weight polyols can contain structural configurations that arenot typical of polyethers used in flexible urethane foams.10.Prepar
16、ation of Sample10.1 Mix 3 mL of polyol with 1.5 to 2 mL of deuteratedchloroform or deuterated acetone.Transfer an appropriateamount to the NMR tube.11.Instrument Preparation11.1 Prepare a decoupled carbon-13 NMR experiment,se-lecting appropriate parameters to obtain quantitative integra-tion of the peaks in the 67-60 ppm region.11.2 The settings presented here are examples that apply toa Bruker WP-80 spectrometer and a Varian AC 300 spectrom-eter.Instrument settings for other spectrometers vary.
