ASTM_D_2702_-_05_2011.pdf

Designation:D270205(Reapproved 2011)Standard Practice forRubber ChemicalsDetermination of Infrared AbsorptionCharacteristics1This standard is issued under the fixed designation D2702;the number immediately following the designation indicates the year oforiginal adoption or,in the 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.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This practice covers a simple,rapid practice to prove theidentity of a rubber chemical before incorporation into a rubbermix by comparison of its infrared absorption spectrum withthat of a reference specimen.1.2 This technique can also be used to detect gross contami-nation or large differences in rubber chemicals.Thus,it canprovide a basis for producer-consumer agreement.1.3 Wherever“infrared spectrophotometer”is used,“Fou-rier Transform Infrared Spectrometer(FTIR)”may also beunderstood.1.4 This standard does not 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.2.Referenced Documents2.1 ASTM Standards:2E131 Terminology Relating to Molecular SpectroscopyE168 Practices for General Techniques of Infrared Quanti-tative AnalysisE275 Practice for Describing and Measuring Performance ofUltraviolet and Visible Spectrophotometers3.Terminology3.1 Definitions:For definitions of terms used in this practicerefer to Terminology E131.4.Summary of Practice4.1 A method of specimen preparation is selected that iscompatible with the physical and chemical properties of therubber chemical that will provide the desired spectral informa-tion.4.2 The specimen is placed in the specimen beam of thespectrophotometer and scanned to obtain a spectrum over theregion of interest under specified instrument parameters.4.3 The spectrum is compared with that of a referencespecimen.It is understood that the reference specimen wasprepared and scanned in an identical manner and preferably onthe same infrared spectrophotometer.5.Significance and Use5.1 This procedure can be used for a variety of applications,including identifying unlabeled material,process control,rawmaterial acceptance,product evaluation,and compositionalchange during environmental testing.5.2 Rubber chemicals vary widely in their chemical andphysical properties.Infrared spectrophotometers vary in thepresentation of a spectrum(some are linear with absorbance,others with transmittance,some use grating for energy disper-sion,others use a sodium chloride prism,some obtain aspectrum through a mathematical Fourier Transform,and thelike).For these reasons,a single universal method of specimenpreparation and set of instrument parameters is not possible.5.3 By using a specific sampling procedure and operatingconditions,a given spectrophotometer will give an absorptioncurve that is characteristic of the rubber chemical or mixtureunder investigation.5.4 The ability to superimpose the infrared spectrum of thetest specimen upon that of a reference specimen,obtainedunder the same conditions,is evidence that the two areidentical.5.5 The presence of additional absorption bands in either thetest specimen or the reference specimen indicates the presenceof one or more additional components.1This practice is under the jurisdiction ofASTM Committee D11 on Rubber andis the direct responsibility of Subcommittee D11.11 on Chemical Analysis.Current edition approved Nov.1,2011.Published January 2012.Originallyapproved in 1968.Last previous edition approved in 2005 as D2702 05.DOI:10.1520/D2702-05R11.2For 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 standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.Apparatus6.1 Initial Specimen PreparationThe diverse physical na-ture of rubber chemicals may require the use of one or more ofthe following:6.1.1 Agate Mortar and Pestle,small.6.1.2 Wig-L-Bug Amalgameter.36.1.3 Mold and Press for KBr PelletsThe die size willdepend on the disk holder available with the users infraredspectrophotometer.The hydraulic press should be capable ofexerting 140-MPa(20 000-psi)pressure.6.1.4 Vacuum Pump,operating at 250 Pa or less.6.2 Infrared Spectrophotometer:6.2.1 The spectral region from 2.5 to 15 m(4000 to 667cm1)is the region most often used for rubber chemicalidentification,although inorganic chemicals may have usefulbands down to 250 cm1.6.2.2 If the performance of the spectrophotometer must beevaluated,refer to Practice E275.6.3 Demountable CellsLiquid cells ranging from 0.02