1、Designation: D5044 06 (Reapproved 2017)Standard Test Method forRubber Compounding MaterialsFree2-Mercaptobenzothiazole (MBT) in Benzothiazyl Disulfide(MBTS)1This standard is issued under the fixed designation D5044; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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 procedure for estimation ofthe acidic impurit
3、ies in benzothiazyl disulfide (MBTS).1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the us
4、er of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on
5、 Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4483 Practice for Evaluating Precision for Test Me
6、thodStandards in the Rubber and Carbon Black ManufacturingIndustries3. Summary of Test Method3.1 A sample of MBTS is dissolved in solvent. Afteraddition of an acetate buffer, water, and starch solution, thesolution is titrated with iodine.3.2 MBTS is sparingly soluble in any organic solvent. MBT,maj
7、or impurity in MBTS, is very soluble. Stirring thereforewill dissolve MBT, MBTS could stay undissolved.4. Significance and Use4.1 2-Mercaptobenzothiazole (MBT) is usually the majorimpurity in MBTS. Free MBT may be determined by this testmethod.4.2 MBT and MBTS are used for rubber and latex vulcani-z
8、ation acceleration. The amount of MBT in MBTS may be ofimportance in predicting performance in rubber compoundsand for raw material purchase and control.4.3 This test method may be used as a quality control tooland for research and development work.5. Apparatus5.1 Erlenmeyer Flask, 300-cm3.5.2 Gradu
9、ated Cylinders, 10-cm3, 50-cm3, 250-cm3.5.3 Buret, 10-cm3.5.4 Analytical Balance, having a sensitivity of 60.1 mg.6. Reagents6.1 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
10、 Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other 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.6.2 Purity of Wat
11、erUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Types I, II, or III of Specification D1193.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand Rubber-like Materials and is the direct responsibility of Subcommittee D11
12、.11on Chemical Analysis.Current edition approved May 1, 2017. Published June 2017. Originallyapproved in 1990. Last previous edition approved in 2012 as D5044 06 (2012).DOI: 10.1520/D5044-06R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at s
13、erviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the Ame
14、rican Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken
15、, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organizati
16、on Technical Barriers to Trade (TBT) Committee.16.3 Isopropanol, analytical reagent.6.4 Toluene, analytical reagent.6.5 Acetic Acid, 100 % analytical reagent.6.6 Sodium Acetate, analytical reagent.6.7 Water, distilled.6.8 Iodine Solution (0.1 N).6.9 Starch Indicator SolutionSlurry2gofsoluble starchw
17、ith 10 cm3of water and dilute with 90 cm3of boiling water.6.10 Sodium Acetate SolutionDissolve 60 g of sodiumacetate in water to make 600 cm3of solution.6.11 Acetate-BufferAdd 100 cm3acetic acid (see 6.5)to600 cm3sodium acetate solution (6.10).6.12 SolventMix 5 volumes Isopropanol with 3 volumestolu
18、ene.7. Sampling7.1 Sampling shall be at the discretion of the analyst toobtain as representative a sample as possible of the lot to betested.8. Procedure8.1 Accurately weigh about1gofthetest specimen to thenearest 0.1 mg and carefully transfer to a 300-cm3Erlenmeyerflask.8.2 Add 50 cm3of solvent to
19、the specimen which may notdissolve completely.8.3 With stirring, add the reagents in the following se-quence: 150 cm3distilled water, 10 cm3acetate buffer, and5cm3starch solution.8.4 Titrate immediately with 0.1 N iodine solution until thecolor change from colorless to light violet is stable for 1 m
20、in.(See 3.2)8.5 Obtain a blank titration by proceeding from steps 8.2through 8.4.9. Calculation9.1 Calculate the percent free MBT as follows:Percent Free MBT 5A 2 B! 3 N 30.1672W3100 (1)where:A = volume of iodine (see 6.7) required for titration ofthe sample, cm3,B = volume of iodine (see 6.7) requi
21、red for titration ofthe blank, cm3,W = mass of the test specimen in g,N = normality of the iodine solution, and0.1672 = millimole mass of MBT.10. Report10.1 Report the following information:10.1.1 Proper identification of the sample and10.1.2 Results obtained from two individual determinationsand th
22、eir average, reported to the nearest 0.1 %.11. Precision and Bias411.1 This precision and bias section has been prepared inaccordance with Practice D4483. Please refer to this practicefor terminology and other statistical calculation details.11.2 The precision results in this precision and bias sect
23、iongive an estimate of the precision of this test method with thematerials (rubbers, etc.) used in the particular interlaboratoryprogram as described below. The precision parameters shouldnot be used for acceptance or rejection testing of any group ofmaterials without documentation that the paramete
24、rs are appli-cable to the particular group of materials and the specifictesting protocols of the test method.11.3 A Type 1 interlaboratory test program (ITP) wasconducted in 1997 on a sample of IRM-MBTS. Six laborato-ries participated in the ITP conducting duplicate tests on eachof 2 successive test
25、 days.Atest result for free MBT is the valueobtained from one analysis operation. The database generatedby this ITP was divided into two parts; Part 1 used the first ofthe duplicates on each day and Part 2 used the second of theduplicates. A complete statistical analysis according to D4483was conduc
26、ted for each part. The results of each part wherethen combined (averaged) for the final values as given in thissection. Thus the precision results pertain to between daysingle determinations for free MBT.11.4 The data of the ITP showed that two laboratories couldnot detect free MBT with good sensiti
27、vity reporting only lessthan 0.2 % for all analysis runs. The data for these two weredeleted from the analysis and thus the reported precision isbased on a four laboratory database. This is an insufficientnumber of laboratories for a reliable assessment of precisionbut it is given as the best effort
28、 as of this time.11.5 RepeatabilityThe repeatability r, of this test methodhas been established as the value tabulated in Table 1.Twosingle test results, obtained under normal test methodprocedures, that differ by more than this tabulated r (for anygiven level) must be considered as derived from dif
29、ferent ornon-identical sample populations.11.6 ReproducibilityThe reproducibility R, of this testmethod has been established as the value tabulated in Table 1.Two single test results obtained in two different laboratories,under normal test method procedures, that differ by more than4Supporting data
30、have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D11-1083.TABLE 1 Precision for Free MBT in MBTSAMean Within-Laboratory Between LaboratoryMaterial Value (a) Sr r (r) SR R (R)IRM-MBTS 0.179 0.00604 0.017 9.5 0.0365 0.103 57.4APrecision results for
31、 4 laboratories, mean value for free percent MBT.Sr = repeatability standard deviationSR = reproducibility standard deviationr = repeatability, in measurement unitsR = reproducibility, in measurement units(r) = repeatability (relative) in percent(R) = reproducibility (relative) in percentD5044 06 (2
32、017)2the tabulated R must be considered to have come from differentor non-identical sample populations.11.7 BiasIn test method terminology, bias is the differencebetween an average test value and the reference (or true) testproperty value. Reference values do not exist for this testmethod since the
33、value (of the test property) is exclusivelydefined by the test method. Bias cannot therefore be deter-mined.12. Keywords12.1 mercaptobenzothiazole; mercaptobenzothiazoledisul-fideASTM International takes no position respecting the validity of any patent rights asserted in connection with any item me
34、ntionedin 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 standard is subject to revision at any time by the responsible technical committe
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36、ng 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.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO
37、 Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 06 (2017)3
