1、Designation:D550894a(Reapproved 2009)1Standard Test Method forDetermination of Residual Acrylonitrile Monomer in Styrene-Acrylonitrile Copolymer Resins and Nitrile-ButadieneRubber by Headspace-Capillary Gas Chromatography(HS-CGC)1This standard is issued under the fixed designation D5508;the number i
2、mmediately 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.1NOTEReapproved wit
3、h editorial changes in April 2009.1.Scope*1.1 This test method covers the determination of the re-sidual acrylonitrile(RAN)content in nitrile-butadiene rubbers(NBR),styrene-acrylonitrile(SAN)copolymers,and rubber-modified acrylonitrile-butadiene-styrene(ABS)resins.1.2 Any components that can generat
4、e acrylonitrile in theheadspace procedure will constitute an interference.The pres-ence of 3-hydroxypropionitrile in latices limits this procedureto dry rubbers and resins.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility o
5、f 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 6.3 and 6.4.NOTE1There is no known ISO equivalent to this test method.2.Referenced Documents2.1 AS
6、TM Standards:2E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Summary of Test Method3.1 Two dispersions(in o-dichlorobenzene)are preparedand sealed in headspace vials for each polymer;one vialcontains the polymer in solvent while the second vial cont
7、ainsthe polymer,solvent,plus a known standard addition ofacrylonitrile(AN).Both vials are agitated for a specified timeunder ambient conditions.After agitation,the vials are ther-mally equilibrated in a constant-temperature bath.3.2 After completion of the timed equilibration,an aliquotof the heated
8、 headspace gas from each vial is injected into acapillary gas-chromatographic column.An automated injectionsystem is used to effect the transfer.The capillary column willprovide the chromatographic resolution necessary to isolate theAN from other volatiles potentially present.The AN responseis measu
9、red using a nitrogen-specific detector(NPD).The rawdata signal is converted to a relative RAN concentrationthrough a standard addition calculation.4.Significance and Use4.1 A measurement of the residual acrylonitrile in nitrilerubbers(NBR),styrene-acrylonitrile copolymers or ABS ter-polymers will de
10、termine the polymers suitability for variousapplications.4.2 Under optimum conditions,the minimum level of de-tection of RAN in NBR,SAN,or ABS terpolymers is approxi-mately 50 ppb.5.Apparatus5.1 Gas Chromatograph,equipped with a nitrogen-phosphorus specific detector,backflush valve(see Fig.1),spliti
11、njector,and capable of accepting megabore(0.53 mm insidediameter)fused silica capillary columns.Detector make-up gasis required.NOTE2The use of a backflush configuration will provide foroperating advantages,but its use is optional.Chlorinated solvents quenchthe alkali bead in a nitrogen-phosphorous
12、detector,producing a loss ofsignal.While the bead(signal)will recover as the solvent evacuates thedetector,repeated quenching during a multi-run sequence may produceinstabilities in the signal(and precision)over the sequence period.5.2 Automated Headspace Sampler,shall have a thermost-atted sample t
13、ray capable of 90C heating with constantheating times.Automated sampling of the headspace gas in thesample vials via a heated,constant-volume sample loop or1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytic
14、al Methods andSection D20.70.02 on Chromatography.Current edition approved April 1,2009.Published April 2009.Originallyapproved in 1994.Last previous edition approved in 2001 as D5508-94a(2001)1.DOI:10.1520/D5508-94AR09E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact
15、ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohock
16、en,PA 19428-2959.United States1 pressure balancing sampling mechanism is required.Conductsampling to the gas chromatograph by means of a heatedtransfer line of minimum dead volume.5.3 Fused Silica Porous-Layer-Open-Tubular(PLOT)Cap-illary Column3,GS-Q,30 m 0.53 mm inside diameter.NOTE3The column should be cut so as to have a 3 m section for thepre-column(Column 1)and a 27-m section for the analytical column(Column 2).5.4 Variable Restrictor.45.5 Data-Recording DeviceA strip-chart recorder,record
