ASTM_D_6844_-_10_2015.pdf

Designation:D684410(Reapproved 2015)Standard Test Method forSilanes Used in Rubber Formulations(bis-(triethoxysilylpropyl)sulfanes):Characterization by HighPerformance Liquid Chromatography(HPLC)1This standard is issued under the fixed designation D6844;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 characterization of silanes,or of admixtures of silane and carbon black(see 10.4),of thetype bis-(triethoxysilylpropyl)sulfane by high performanceliquid chromatography.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 user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D5297 Test Methods for Rubber Chemical AcceleratorPurity by High Performance Liquid ChromatographyE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE682 Practice for Liquid Chromatography Terms and Rela-tionshipsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 SxBis-(triethoxysilylpropyl)polysulfaneorpolysulfide,(EtO)3SiC3H6SxC3H6Si(OEt)33.1.2 S2Bis-(triethoxysilylpropyl)disulfane or disulfide,(EtO)3SiC3H6S2C3H6Si(OEt)33.1.3 S3Bis-(triethoxysilylpropyl)trisulfane or trisulfide,(EtO)3SiC3H6S3C3H6Si(OEt)33.1.4 S3Bis-(triethoxysilylpropyl)tetrasulfaneortetrasulfide,(EtO)3SiC3H6S4C3H6Si(OEt)33.1.5 S3Bis-(triethoxysilylpropyl)pentasulfaneorpentasulfide,(EtO)3SiC3H6S5C3H6Si(OEt)33.1.6 S3Bis-(triethoxysilylpropyl)hexasulfaneorhexasulfide,(EtO)3SiC3H6S6C3H6Si(OEt)33.1.7 S3Bis-(triethoxysilylpropyl)heptasulfaneorheptasulfide,(EtO)3SiC3H6S7C3H6Si(OEt)33.1.8 S3Bis-(triethoxysilylpropyl)octasulfaneoroctasulfide,(EtO)3SiC3H6S8C3H6Si(OEt)33.1.9 S3Bis-(triethoxysilylpropyl)nonasulfaneornonasulfide,(EtO)3SiC3H6S9C3H6Si(OEt)33.1.10 S3Bis-(triethoxysilylpropyl)decasulfaneordecasulfide,(EtO)3SiC3H6S10C3H6Si(OEt)33.1.11 average sulfur chain lengththe weighted averageof the sulfur bridge in the polysulfide mixture.Includes S2toS10species.4.Summary of Test Method4.1 A sample of the silane is analyzed by high performanceliquid chromatography to determine amounts of eachcomponent,the average chain length and the amount ofdissolved elemental sulfur.4.2 Two methods are described:Method A with a constantcomposition of the mobile phase(isocratic),and Method Busing a gradient.Both methods will give similar chromato-grams.5.Significance and Use5.1 The average sulfur chain length is an important param-eter in determining the behavior of the silane in a rubbermixture.6.Apparatus6.1 HPLC with UV Detector,operating at 254 nm,InletValve with 5 mm3(L)loop,integrator or data system.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.20 on Compounding Materialsand Procedures.Current edition approved June 1,2015.Published September 2015.Originallyapproved in 2002.Last previous edition approved in 2010 as D6844 10.DOI:10.1520/D6844-10R15.2For 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 States1 6.2 Column C18,5 m,4.6 250 mm.6.3 Column Oven.6.4 Analytical Balance,accuracy 60.1 mg.6.5 Hamilton Syringe,100 mm3(L).6.6 Volumetric Pipet,5 cm3.6.7 Volumetric Flasks,50 and 2000 cm3.6.8 Syringe,3 cm3or 5 cm3.6.9 Glass Bottles,5 cm3.6.10 Disposable PTFE Filters,0.20 m,d=25 mm.6.11 Mechanical Flask Shaker.7.Reagents,AR Grade or Equivalent7.1 Reagents for Method A(without gradient):7.1.1 Ethanol,absolute.7.1.2 Methanol.7.1.3 Tetrabutylammoniumbromide.7.1.4 Cyclohexane.7.1.5 Sulfur.7.1.6 Deionised Water.7.2 Reagents for Method B(with gradient):7.2.1 2-Propanol(IPA).7.2.2 Acetonitrile(AcCN).7.2.3 Tetrabutylammoniumbromide.7.2.4 Hexane.7.2.5 Sulfur.7.2.6 Mesitylene.7.2.7 Deionised Water.8.Preparation of Solutions8.1 Tetrabutylammoniumbromide SolutionDissolve 400mg of tetrabutylammoniumbromide in 1000 cm3of deionisedwater.8.2 Mobile Phase:8.2.1 Mobile Phase for Method A(Isocratic)Transfer 180cm3of tetrabutylammoniumbromide solution and 450 cm3ethanol into a 2000 cm3volumetric flask.Make up to the markwith methanol and mix well.NOTE1Separation between peaks of the silane species and elementalsulfur can be optimized by carefully