ASTM_D_7132_-_14.pdf

Designation:D713214Standard Test Method forDetermination of Retained Blowing Agent in ExtrudedPolystyrene Foam1This standard is issued under the fixed designation D7132;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.1.Scope*1.1 This test method covers the determination of retainedblowing agent in extruded polystyrene foam.1.2 This test method applies to organic blowing agentswhich lend themselves to a convenient analysis by gas chro-matography.The method is not applicable to blowing agentssuch as nitrogen,carbon dioxide,or water.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 to determine theapplicability of regulatory limitations prior to use.NOTE1There is no known ISO equivalent to this standard.2.Summary of Test Method2.1 Polystyrene foams are made with a variety of blowingagents such as hydrocarbons,hydrofluorocarbons,ethers,ketones,and other volatile organic chemicals.A fraction of theblowing agent used in the manufacture of foam is retained inthe product,some residing in the cell walls and some entrappedinside the cells.This test method is based on releasing theretained blowing agent by dissolving the polystyrene foam in asolvent,such as toluene,and then analyzing the solution for itscomponents by gas chromatography.An internal standard isused as a reference analyte and calibration of the gas chro-matograph(GC)with standard solutions allows conversion ofthe GC response to the amount of blowing agent retained in thefoam matrix.3.Interferences3.1 The gas chromatogram has the potential to contain asignal(s)from the polymer matrix that interferes with thesignal(s)from the blowing agent components.Test calibrationsolutions with and without the polymer matrix to rule out anyinterference.These calibration solutions shall contain about thesame amount of dissolved resin as in the foam sample beinganalyzed.4.Apparatus4.1 Any GC equipped with a column suitable for resolvingblowing agent components is suitable for use.For example,ifseparating non-polar blowing agents,a 100%dimethyl-polysiloxane with 530-m thick film and 30-m length is areasonable selection.If separating polar blowing agents,a 50%dipheny/50%dimethyl polysiloxane column with 530-mthick film and 30-m length is suitable.Typical operatingparameters for the GC are:Head pressure(kPa)50Initial oven temperature(C)50Initial hold time(min)3.5Temperature program rate(C/min)25Final temperature(C)150Final hold time(min)3Injector temperature(C)250Detector temperature(C)300Carrier gasHeCarrier gas flow rate(cm3/min)30Injection sample size(L)0.2NOTE2An autosampler is not recommended as the transfer of asolution containing volatile components can lead to loss of the volatileanalyte.4.2 Analytical balance with at least 150 g full scale and 0.1mg resolution.4.3 Instrument grade air supplied at 515 6 40 kPa,heliumat 450 6 40 kPa,and hydrogen at 380 6 40 kPa.4.4 100-cm3volumetric flasks.4.5 1-cm3syringe with Chaney Adapter,and 10-cm3gastight syringe with Chaney Adapter.4.6 1-L syringe.4.7 Tall,wide mouth 125-cm3sample bottles with caps andteflon/silicon septa.4.8 30-cm3serum vials with crimp on teflon/silicon septa.4.9 Rubber sleeve stoppers for volumetric flask.4.10 Septa for GC.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved March 1,2014.Published March 2014.Originallyapproved in 2005.Last previous edition approved in 2013 as D7132 13.DOI:10.1520/D7132-14.*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 States1 4.11 Ice water bath.4.12 Weights to keep sample bottle submerged.4.13 Refrigerator for sample storage.4.14 Insulated mailing containers with ice packs for ship-ping samples.5.Reagents and Materials5.1 Certified grade toluene with minimum purity of 99.8mol%.5.2 Certified grade normal heptane with minimum purity of99.8 mol%.5.3 Instrument grade standards for blowing agents to beanalyzed.6.Hazards6.1 Some blowing agents are compressed liquids or gases atroom temperature.Appropriate care shall be taken whenpreparing calibration solutions from such blowing agents.7.Sampling,Test Specimens,and Test Units7.1 Record the manufacture date of the foam and the date ofmaterial sampling.7.2 Tare sample bottle with cap and septum.Cut a piece offoam using a sharp knife,transfer it immediately to the sampl