1、Designation: D 2121 07Standard Test Methods forPolymer Content of Styrene Monomer and AMS(aMethylstyrene)1This standard is issued under the fixed designation D 2121; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 and AMS (aMethylsty-rene). It should
3、be noted, however, that dimers and trimers arenot measured by these test methods.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 orAMS in concentrations up to 15 mg/kg. Samples
4、 containingmore than 15 mg/kg of polymer must be suitably diluted beforemeasurement.1.3 Test Method B is a rapid visual procedure that isintended for the approximate evaluation of polymer to amaximum concentration of 1.0 weight %. Samples having apolymer content of 1.0 weight % or greater should be
5、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 u
6、nits 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 re
7、gulatory limitations prior to use. For specific hazardstatements, see Section 8.2. Referenced Documents2.1 ASTM Standards:2D 2827 Specification for Styrene MonomerD 3437 Practice for Sampling and Handling Liquid CyclicProductsD 6809 Guide for Quality Control and Quality AssuranceProcedures for Aroma
8、tic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 Other Document:OSHA Regulations,29CFR, paragraphs 1910.1000 and1910.12003TEST METHOD ADETERMINATION OF POLYMERIN STYRENE MONOMER OR a METHYLSTYRENEPHOTOMETER M
9、ETHOD3. Summary of Test Method3.1 This test method utilizes the fact that polymers presentin the monomers are insoluble in methanol. The polymercontent of styrene monomer or AMS is determined by mea-surement of the degree of turbidity produced by the addition ofdry methanol to the styrene or AMS sam
10、ple.4. Significance and Use4.1 This test method can be used for determining polymerconcentrations in styrene monomer or AMS.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 tu
11、rbidity 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 styrene or AMS, and5.2.2 To indicate dissolved water in the styren
12、e or AMS.6. Apparatus6.1 Pipets, 10 and 15-mL.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 AtomaticHydrocarbons.Current edition approv
13、ed Jan. 1, 2007. Published January 2007. Originallyapproved in 1962. Last previous edition approved in 2000 as D 2121 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refe
14、r 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.1*A Summary of Changes section appears at the end of this standard.Copyright
15、ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Bottles or Flasks, of suitable size equipped with glassstoppers.6.3 Spectrophotometer or Photometer Cells, with 50 to150-mm light path.6.4 Spectrophotometer or Photometer, capable of absor-ban
16、ce measurements in wavelength region of 420 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 o
17、n 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, d
18、ry.7.4 Polystyrene:7.4.1 Prepare polystyrene as follows: wash 50 mLof styrenemonomer twice with equal volumes of 1 N NaOH solution andtwice with equal volumes of water. After the second waterwash, filter the styrene through two layers of rapid filteringready folded filter paper. Pour about 20 mL of
19、this styrenemonomer into a test tube and heat in an oven at 100C for 24h to promote polymerization. At the end of this time, removethe polystyrene from the test tube by breaking the tube anddiscarding all glass. Grind the polymer plug to a fine powder inan agate mortar.7.4.2 Commercially available h
20、igh-purity polystyrene pel-lets can be used; however, high-molecular weight polystyrene( 150 000 molecular weight) should be specified.7.5 Styrene Monomer, conforming to Specification D 2827.7.6 Toluene, dry.8. Hazards8.1 Styrene monomer is flammable and polymerizes exo-thermically on contact with p
21、eroxides, mineral acids andaluminum chloride.8.2 Styrene monomer both in liquid and vapor state, when insufficient concentrations, acts as an irritant to the eyes andrespiratory tract.8.3 Consult current OSHA regulations, local regulations,and suppliers Material Safety Data Sheets for all materialsu
22、sed in these test methods.9. Sampling and Handling9.1 Sample the material in accordance with PracticeD 3437.10. Calibration10.1 ApparatusPrepare and operate the spectrophotom-eter or photometer in accordance with the manufacturersinstructions.10.2 Reference Standards and Blanks:10.2.1 Dissolve 0.090
23、5 g of polystyrene in 1000 mL oftoluene measured at 25C, which is equivalent to 100 mg/kg ofpolymer in monomer. This serves as the standard for polymerin styrene and polymer in AMS.10.2.2 Make standard solutions containing 1, 3, 6, 9, 12, and15 mg/kg of styrene polymer by diluting 1, 3, 6, 9, 12, an
24、d 15mL of the 100 mg/kg standard solution to 100 mL with toluenein a volumetric flask at 25C.10.3 Calibration Curves and Tables:10.3.1 Into each of a series of bottles equipped with glassstoppers pipet 15 mL of dry methanol and 10 mL of a polymerstandard and mix thoroughly. Into another series of bo
25、ttlespipet 15 mL of hexane and 10 mL of each polymer standardand mix thoroughly. Other volumes may be used, depending onthe capacity of the spectrophotometer cell as long as the 3:2proportion is maintained.10.3.2 Allow the solutions to stand in the stoppered bottlesfor 15 min 6 1 min (Note 1). At th
26、e end of this time, pour thesolutions into the spectrophotometer cells and measure theabsorbance of each at a wavelength of 420 nm using thehexane/polymer standard as the blank (Note 2).NOTE 1Small changes in turbidity may occur with time. It is,therefore, important that the absorbance of calibratio
27、n mixtures andsamples be determined after standing the same length of time.NOTE 2The hexane is used for two reasons: (1) to blank out any colorin the styrene, and (2) to indicate dissolved water in the styrene.10.3.3 Prepare a calibration curve by plotting the absor-bance against the milligrams per
28、kilogram of polymer.11. Procedure11.1 Pipet 15 mL of hexane into a bottle equipped with aglass stopper.11.2 Into a second bottle, pipet 15 mL of dry methanol.11.3 Add 10 mL of styrene monomer or AMS to each bottleand mix thoroughly.11.4 Proceed as described in 10.3.2 using the hexanemixture as the b
29、lank.12. Calculation12.1 Read the milligrams per kilogram of polymer directlyfrom the calibration curve.NOTE 3Milligrams per kilogram can be converted to weight percentby dividing by 10 000.13. Report13.1 Report the polymer content of the sample as milli-grams of polymer per kilogram of monomer to t
30、he nearestmg/kg. For results less than 1 mg/kg, report /mg/kg.4Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals,
31、BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D212107214. Precision and Bias14.1 Intermediate Precision (formerly calledRepeatability)Duplicate results by the same operator shouldnot be considered sus
32、pect unless they differ by more than thefollowing amount:Range, mg/kg Repeatability, mg/kg1to15 0.514.2 ReproducibilityResults submitted by each of twooperators using the same apparatus should not be consideredsuspect unless they differ by more than the following amount:Range, mg/kg Reproducibility,
33、 mg/kg1to15 1.014.3 BiasSince there is no accepted reference materialsuitable for determining bias for the procedure in these testmethods, bias has not been determined.15. Quality Guidelines15.1 Refer to Guide D 6809 for suggested QA/QC activitiesthat can be used as part of this test method. It is r
34、ecommendedthat the operator of this test method select and perform relevantQA/QC activities like the ones in Guide D 6809 to help ensurethe quality of the data generated by this test method.TEST METHOD BVISUAL EVALUATION OFPOLYMER CONTENT OF STYRENE MONOMER ORAMS16. Summary of Test Method16.1 This t
35、est method utilizes the fact that styrene polymersare insoluble in methanol. The polymer content of a sample ofstyrene monomer orAMS is evaluated by visual observation ofthe degree of turbidity produced by the addition of methanol tothe sample. The order of magnitude of the polymer content ofstyrene
36、 monomer or AMS in the incremental steps 0.001, 0.01,0.1, and 1.0 weight % may readily be differentiated visually.For 0 % observe pure dry methanol.17. Apparatus17.1 Test Tube, 25 by 150-mm.17.2 Pipets, 2 and 10-mL.17.3 Daylight Fluorescent Tube, equipped with curved re-flector.18. Reagents18.1 Meth
37、anol, dry.18.2 Polystyrene, uncolored, unfilled, unlubricated (see7.4).18.3 Toluene, dry.19. Procedure19.1 Pipet 2 mL of sample into a clean, dry test tube, add 10mL of dry methanol by means of a pipet, stopper the test tubewith a cork covered with aluminum foil, and shake vigorouslyfor a few second
38、s.19.2 After shaking the test tube, inspect the mixture visuallyby looking through it toward a source of artificial daylight.Compare the observed turbidity of the mixture with thedescriptions of turbidity given in Table 1 or against knownstandards. If standards are desired, they may be prepared usin
39、gpolystyrene and toluene.20. Report20.1 From Table 1 select the turbidity description that mostnearly approximates that of the sample, and report the corre-sponding polymer content.21. Keywords21.1 amethylstyrene; AMS; polymer; polymer content;styrene; styrene monomerSUMMARY OF CHANGESCommittee D16
40、has identified the location of selected changes to this standard since the last issue(D 2121 - 00) that may impact the use of this standard. (Approved January 1, 2007.)(1) 1.4 revised statement.(2) Section 2 revised format of footnotes.(3) Section 9 revised title.(4) Section 10 revised title.(5) Sec
41、tion 15 added new section.TABLE 1 Relationship Between Polymer Content of StyreneMonomer and Turbidity of Mixture of Two Parts by VolumeStyrene Monomer and Ten Parts by Volume Dry MethanolPolymer Content ofStyrene Monomerby Weight, %ADescription of Turbidity ofStyrene-Methanol Mixture1.0 or greater
42、milk-white opaque liquid with heavy white precipitate0.1 milk-white opaque liquid with no evidence ofsedimentation0.01 cloudiness readily visible, but mixture still transparent0.001 faint trace of cloudiness; detectable only by comparisonwith pure dry methanolNone no cloudiness discernible by compar
43、ison with pure drymethanolAIt is suggested that the analyst initially perform the test using referencemixtures described in this table as a guide. An experienced analyst can estimatethe polymer content reliably without the use of reference mixtures.D2121073ASTM International takes no position respec
44、ting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This sta
45、ndard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Internati
46、onal Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below
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