ASTM_D_6741_-_10_2015.pdf

Designation:D674110(Reapproved 2015)Standard Test Methods forSilanes Used in Rubber Formulations(bis-(triethoxysilylpropyl)sulfanes):Sulfur Content1This standard is issued under the fixed designation D6741;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 These test methods cover the determination of the sulfurcontent of silanes,or of admixtures of silane and carbon black,of the type bis-(triethoxysilylpropyl)sulfane.The following testmethods are included:Test Method A:Combustion in an Oxygen Flask and SubsequentTitration of SulfateTest Method B:High-Temperature Combustion with InfraredAbsorption Detection1.2 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:2D1193 Specification for Reagent WaterE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Significance and Use3.1 The sulfur content can be used to characterize a silane oran admixture of silane and carbon black.It depends mainly onthe average length of the sulfur chain.Test Method A:Combustion in an Oxygen Flask andSubsequent Titration of Sulfate4.Summary of Test Method4.1 The weighed sample is burned in an oxygen atmo-sphere.The resulting sulfur dioxide and trioxide is absorbed inhydrogen peroxide solution,and the sulfate ions thus generatedare titrated with barium perchlorate solution employing Thorinindicator.Taking into account the known concentration of theperchlorate solution,the volume consumed,and the samplemass,the sulfur content of the sample can be calculated.5.Apparatus5.1 Analytical Balance,accuracy 60.1 mg.5.2 Combustion Apparatus,according to Schoeniger,with750 cm3flask.5.3 Ultrasonic Bath.5.4 Automatic Titrator.5.5 Photoelectrical Detector,set at 550 nm.5.6 Volumetric Cylinder,100 cm3.5.7 Volumetric Flask,100 cm3.5.8 Volumetric Pipet,10 cm3.5.9 Syringe,0.5 cm3.5.10 Titration Beakers.5.11 Magnetic Stirrer,with stirring rod.5.12 Filter Paper,for Schoeniger combustion(35 35 70mm).5.13 Glass Tube,attached to a rubber hose.6.Reagents6.1 Purity of ReagentsReagent grade shall be used in alltests.Unless otherwise indicated,it is intended that all reagentsshall conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society where1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.20 on CompoundingMaterials and Procedures.Current edition approved June 1,2015.Published September 2015.Originallyapproved in 2001.Last previous edition approved in 2010 as D6741 10.DOI:10.1520/D6741-10R15.2For 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 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 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Specification D1193.6.3 2-propanol 99%.6.4 Hydrogen Peroxide Solution,(5%)as absorbing liquid.6.5 Barium Perchlorate Solution,0.005 mol/dm3in2-propanol/water.6.6 Thorin Solution,0.1%in water(Thorin octahydrate).6.7 Sulfuric Acid,as a standard solution(1.000 6 0.002 gSO42-).6.8 Deionized Water.6.9 Oxygen.6.10 Sulfanilic Acid,(certified standard for elemental analy-sis).7.Preparation of ApparatusNOTE1The flask shall not contain any residues from solvents.Purgewith compressed air if necessary.NOTE2Check flask for damages.Do not use flasks having scratchesor cracks.NOTE3Ignite with safety shield lowered only.NOTE4After combustion is finished,leave flask in the apparatus for5 min cool-down.7.1 Add 20 cm3of 5%H2O2solution into the combustionflask by means of a volumetric cylinder.7.2 Add a magnetic stirring rod.7.3 Purge the flask for 1 min with oxygen gas.Do this bydirecting a gentle stream from the glass tube towards thebottom of the flask.8.Procedure8.1 Preparation of Liquid Samples(Silanes):8.1.1 Place a non-densified cotton wool swab between t