ASTM_D_4934_-_02_2021.pdf

Designation:D493402(Reapproved 2021)Standard Test Method forRubber Compounding Materials:2-BenzothiazylSulfenamide AcceleratorsInsolubles1This standard is issued under the fixed designation D4934;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 a general procedure for thedetermination of insoluble impurities of sulfenamides in suit-able organic solvents.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 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,health,and environmental practices and deter-mine the applicability 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 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:2D4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3.Summary of Test Method3.1 A specimen of sulfenamide is dissolved in a prescribedsolvent,stirred,and filtered through a crucible.The insolublecontent is calculated from the amount of residue.4.Significance and Use4.1 Sulfenamides can degrade in chemical purity and func-tional performance,usually characterized by a drop in assay,arelease of free amine,and an increase in insolubles.This testmethod may be used as an indication of such degradation.4.2 Since MBTS(mercaptobenzothiazole disulfide)is aprimary degradation product of sulfenamides,the determina-tion of MBTS is a means of assessing possible degradation ofsulfenamides.Insolubles are a means of mercaptobenzothiazyldisulfide(MBTS)content of the sulfenamide;MBTS is aprimary degradation product of sulfenamides.Amine salts ofmercaptobenzothiazole(MBT)may also be insoluble.However,certain soluble species may also be generated duringsulfenamide degradation.Consequently,insolubles are not anabsolute measure of purity and can actually decrease withsulfenamide degradation.5.Apparatus5.1 Erlenmeyer Flask,300 cm3.5.2 Sintered Glass Crucible,G4.5.3 Measuring Cylinder,250 cm3.5.4 Magnetic Stirrer.5.5 Watch Glass.5.6 Vacuum Flask.5.7 Explosion-proof,Vented Air Circulating Oven,capableof temperature regulation of 70 6 2C.5.8 Balance,analytical,with a sensitivity of 60.01 g.5.9 Washing Bottle.5.10 Sieve,30 Mesh(U.S.Standard),or equivalent(forexample,0.6 mm).6.Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society where1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand Rubber-like Materials and is the direct responsibility of Subcommittee D11.11on Chemical Analysis.Current edition approved Nov.1,2021.Published January 2022.Originallyapproved in 1989.Last previous edition approved in 2017 as D4934 02(2017).DOI:10.1520/D4934-02R21.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,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 Organization Technical Barriers to Trade(TBT)Committee.1?such specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Methanol,analytical reagent.6.3 Cyclohexane,analytical reagent.7.Hazards7.1 Methanol and cyclohexane,with threshold limit values(TLVs)of 200 cm3/m3and 300 cm3/m3,respectively,and highflammability,should be handled with appropriate caution.7.2 Good laboratory safety practices should be followed inhandling all chemicals and carrying out manipulations.8.Sampling8.1 Sampling shall be at the discretion of the analyst toobtain as representative a sample as possible of the lot to betested.9.Procedure9.1 Solvents:9.1.1 MethanolUsefortestingspecimensofN-cyclohexyl-2-benzothiazole sulf