ASTM_D_4322_-_96_2001.pdf

Designation:D 4322 96(Reapproved 2001)e1Standard Test Method forResidual Acrylonitrile Monomer Styrene-AcrylonitrileCopolymers and Nitrile Rubber by Headspace GasChromatography1This standard is issued under the fixed designation D 4322;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(e)indicates an editorial change since the last revision or reapproval.e1NOTESeveral sections were changed editorially in March 2001.1.Scope1.1 This test method is suitable for determining the residualacrylonitrile(RAN)content of styrene-acrylonitrile(SAN)copolymer,rubber-modified acrylonitrile-butadiene-styrene(ABS)resins,and nitrile rubber(NBR).1.2 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.Specific precau-tionary statements are given in Section 9.NOTE1Although the packed column option of this test method andISO 4581:1994(E)differ in some details,data obtained using either testmethod should be technically equivalent.There is no equivalent ISOstandard for the capillary column option of this test method.2.Referenced Documents2.1 ASTM Standards:D 4526 Practice for Determination of Volatiles in Polymersby Headspace Gas Chromatography2E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3IEEE/ASTM SI-10 Standard for Use of the InternationalSystem of Units(SI):The Modern Metric System43.Terminology3.1 Units and Symbols used in this test method are thoserecommended in IEEE/ASTM SI-10.3.2 Abbreviations:Abbreviations:3.2.1 ANacrylonitrile.3.2.2 RANresidual acrylonitrile.3.2.3 SANstyrene-acrylonitrile copolymer.3.2.4 ABSacrylonitrile-butadiene-styrene copolymer.3.2.5 NBRbutadiene-acrylonitrile rubber.3.2.6 DMACN,N-dimethylacetamide.3.2.7 PNpropionitrile(internal standard).3.2.8 PCpropylene carbonate.3.2.9 ppmg RAN/g polymer(parts per million).4.Summary of Test Method4.1 A dispersion of the polymer in a suitable solvent isprepared in a headspace vial and sealed.The vial is thermallyequilibrated in a constant temperature bath.4.2 After equilibrium,a given portion of the sample head-space is injected into a gas chromatographic column packedwith porous polymer beads or a capillary column coated withan appropriate liquid phase.Sample injection is achieved usingavailable commercial automatic equipment or a manual syringeinjection technique.Passing through the column in a stream ofcarrier gas,acrylonitrile is separated from other componentsthat may be present.The response of acrylonitrile is measuredby a nitrogen-specific detector for packed column analysis or aflame ionization detector for capillary column analysis and thissignal is recorded to indicate the retention time and relativeconcentration of acrylonitrile.5.Significance and Use5.1 For various reasons one may wish to measure theamount of unreacted or residual acrylonitrile monomer instyrene-acrylonitrile copolymers,nitrile rubbers,or ABS ter-polymers.5.2 Under optimum conditions,the lowest level of detectionof AN in SAN or ABS copolymers and NBR rubbers isapproximately 0.5 ppm for the packed column test method and3 ppm for the capillary test method.6.Interferences6.1 The nitrogen-specific detector eliminates interferencefrom all but compounds containing nitrogen or phosphorus.Any such material eluting at or near the AN or PN retention1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved Dec.10,1996.Published May 1997.Originallypublished as D 4322 83.Last previous edition D 4322 83(1991)e1.This revision includes the addition of an ISO equivalency statement and asuitable capillary column headspace GC test method.2Annual Book of ASTM Standards,Vol 08.03.3Annual Book of ASTM Standards,Vol 14.02.4Annual Book of ASTM Standards,Vol 14.04.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.times will cause erroneous RAN results.The headspace abovea polymer solution containing no internal standard should beanalyzed to determine that no sample peaks coincide with thePN retention time for the packed column test method.Thecapillary column test method specifies use of a flame ionizationdetector.It is an external standard test method,therefore,concern with sample peaks coinciding with the retention timeof the internal standard peak is not an issue.6.2 Normally the headspace will contain only air,RAN,PN,water,solvent,and any other volatile compounds used duringpolymerization.Such impurities at concentrations of 0 to 100ppm will have negligible effect on the equilibrium relat