ASTM_D_2121_-_16.pdf

Designation:D212116Standard Test Methods forPolymer Content of Styrene Monomer1This standard is issued under the fixed designation D2121;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 These test methods cover the determination of thepolymer content of styrene monomer.It should be noted,however,that dimers and trimers are not measured by these testmethods.1.2 Test Method A,which is based on the use of a spectro-photometer or photometer,is intended for the quantitativedetermination of the polymer content of styrene monomer inconcentrations up to 15 mg/kg.Samples containing more than15 mg/kg of polymer must be suitably diluted before measure-ment.1.3 Test Method B is a rapid visual procedure that isintended for the approximate evaluation of polymer to amaximum concentration of 1.0 mass%.Samples having apolymer content of 1.0 mass%or greater should be suitablydiluted prior to measurement.1.4 In determining the conformance of the test results usingthis method to applicable specifications,results shall berounded off in accordance with the rounding-off method ofPractice E29.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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.For specific hazardstatements,see Section 9.2.Referenced Documents2.1 ASTM Standards:2D2827 Specification for Styrene MonomerD3437 Practice for Sampling and Handling Liquid CyclicProductsD4790 Terminology of Aromatic Hydrocarbons and RelatedChemicalsD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Other Document:OSHA Regulations,29CFR paragraphs 1910.1000 and1910.120033.Terminology3.1 See Terminology D4790 for definition of terms used inthis test method.TEST METHOD ADETERMINATION OF POLYMERIN STYRENE MONOMER PHOTOMETER METHOD4.Summary of Test Method4.1 This test method utilizes the fact that polymers presentin the monomers are insoluble in methanol.The polymercontent of styrene monomer is determined by measurement ofthe degree of turbidity produced by the addition of drymethanol to the styrene sample.5.Significance and Use5.1 This test method can be used for determining polymerconcentrations in styrene monomer.5.2 This test method will not detect dimers and trimers.5.3 This test method can be used for plant control and forspecification analysis.6.Interferences6.1 Small changes in turbidity may occur with time.It is,therefore,important that the absorbance of calibration mixturesand samples be determined after standing the same length oftime.1These test methods are under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and are the direct responsibility ofSubcommittee D16.07 on Styrene,Ethylbenzene and C9 and C10 AromaticHydrocarbons.Current edition approved June 1,2016.Published July 2016.Originally approvedin 1962.Last previous edition approved in 2015 as D2121 15.DOI:10.1520/D2121-16.2For 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.3Available from U.S.Government Printing Office Superintendent of Documents,732 N.Capitol St.,NW,Mail Stop:SDE,Washington,DC 20401,http:/www.access.gpo.gov.*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 6.2 Hexane is used for two reasons:6.2.1 To block out any color in the styrene,and6.2.2 To indicate dissolved water in the styrene.7.Apparatus7.1 Pipets,10 and 15-mL.7.2 Bottles or Flasks,of suitable size equipped with glassstoppers.7.3 Spectrophotometer or Photometer Cells,with 50 to150-mm light path.7.4 Spectrophotometer or Photometer,capable of absor-bance measurements in wavelength region of 420 nm andsensitive to 1 mg polymer/kg monomer.8.Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused provi