ASTM_D_7977_-_14.pdf

Designation:D797714Standard Test Methods forPolymer Content of AMS(-Methylstyrene)1This standard is issued under the fixed designation D7977;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.Scope1.1 This test method covers the determination of the poly-mer content of AMS(-Methystyrene).Dimers and trimers arenot measured by these test methods.1.2 This test method has been found applicable to determin-ing the polymer content of AMS in concentrations up to 15mg/kg.Samples containing more than 15 mg/kg of polymermust be suitably diluted before measurement.1.3 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 E29.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 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 8.2.Referenced Documents2.1 ASTM Standards:2D3437 Practice for Sampling and Handling Liquid CyclicProductsD6367 Specification for AMS(-Methylstyrene)D6809 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 Specifications2.2 Other Document:3OSHA Regulations,29 CFR paragraphs 1910.1000 and1910.1200TEST METHOD ADETERMINATION OF POLYMERIN-METHYLSTYRENE VIASPECTROPHOTOMETER3.Summary of Test Method3.1 This test method utilizes the fact that AMS polymerspresent in the monomers are insoluble in methanol.Thepolymer content of AMS monomer is determined by measure-ment of the degree of turbidity produced by the addition of drymethanol to the AMS sample.4.Significance and Use4.1 This test method can be used for determining polymerconcentrations in AMS monomer.4.2 This test method will not detect dimers and trimers.4.3 This test method can be used for plant control and forspecification analysis.5.Interferences5.1 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.5.2 Hexane is used for two reasons:5.2.1 To block out any color in the AMS,and5.2.2 To indicate high levels of dissolved water in theAMS.5.3 Water content was found to have a slight impact on themeasurement of polymer in AMS solution.When the waterconcentration is below 260 ppm,its effect on the measurementof polymer in AMS solution is negligible.6.Apparatus6.1 Class A Volumetric Pipets,10 and 15-mL.1These test methods are under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.07 on Styrene,Ethylbenzene and C9 and C10 AromaticHydrocarbons.Current edition approved Dec.1,2014.Published March 2015.DOI:10.1520/D7977-14.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 Bottles or Flasks,of suitable size equipped with glassstoppers.6.3 Spectrophotometer or Photometer Cells,with 100 to150-mm light path.6.4 Spectrophotometer of Photometer,capable of absor-bance measurements in wavelength region of 330 nm andsensitive to 1 mg polymer/kg monomer.7.Reagents and Materials7.1 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,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Hexane,dry.7.3 Methanol,dry.7.4 Poly-AMS:Commercially available high-purity poly-AMS can be used;low-molecular weight poly-AMS(150 000molecular weight)was found to work and was used in thedevelopment of this standard.7.4.1 Be aware of possible error when the molecular weightof the polymer measured is different from that of the polymerused for calibratio