ASTM_D_5460_-_02_2021e1.pdf

Designation:D546002(Reapproved 2021)1Standard Test Method forRubber Compounding MaterialsWater in RubberAdditives1This standard is issued under the fixed designation D5460;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.1NOTECorrected 7.1 and 9.3 editorially in November 2021.1.Scope1.1 This test method covers a procedure for the determina-tion of water in 2-mercaptobenzothiazole sulfenamide accel-erators by a Karl Fischer coulometric titration.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,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.Terminology2.1 Definitions:2.1.1 inert fillerany nonwater soluble additive used as asupport,binder,processing aid,dedustant,etc.,which may beused in the process of manufacture of a rubber additive.2.1.2 lota production quantity representative of a standardproduction unit.2.1.3 test portionthe actual material used in the analysis;it must be representative of the lot(see 2.1.2).3.Summary of Test Method3.1 The sulfenamide is heated in an oven to remove water.This water is directed into the titration vessel of a Karl Fischercoulometric titrator with a stream of dry air or nitrogen.Thewater collected in the titration vessel is quantified coulometri-cally.Commercial instrumentation exists to carry out thistwo-step procedure automatically.4.Significance and Use4.1 This test method is designed to determine the watercontentofvariousrubberaccelerators.Since2-mercaptobenzothiazolesulfenamideishydrolyticallyunstable,the residual water content is an important character-istic.5.Interferences5.1 The Karl Fischer titration is inherently unreceptive tothe analysis of ketones,aldehydes,and amines.The reagentsystems of Section 7 can be used when free amines are presentif benzoic acid is added to the titration vessel before analysis.The acid serves to adjust the apparent pH difficulties when freeamines are present.Add 5 g of benzoic acid to the titrationvessel before starting a series of analyses.This is renewedwhenever a drift value exceeds 30%of the microgram count orwhen a known amount of water does not produce the correctmicrograms count.5.2 Some rubber chemicals contain amines as part of theirstructure and may release these amines during the heatingprocess.6.Apparatus6.1 Karl Fischer Coulometric Apparatus,equipped with aheating oven to remove water from the test portion placed in it.The water is directed into the titration vessel by means of astream of dry air or nitrogen.The evolved water is quantifiedcoulometrically.The instrument must satisfy conditions foundin 6.2 and Section 9.NOTE1The apparatus must be used by those versed in its operation.It is not the intent or purpose of this test method to instruct the operator.This information is best obtained from manuals supplied by the manufac-turers.6.2 Sample Containers,capable of containing 1 to 4 g of atest portion.1This 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 1993.Last previous edition approved in 2017 as D5460 02(2017).DOI:10.1520/D5460-02R21E01.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?6.3 Balance,capable of weighing a test portion mass to60.1 mg.6.4 Syringes and Needles,to satisfy the requirements of 8.2.7.Reagents7.1 There are a wide variety of reagents on the market forcoulometric analysis.Use the reagent system(s)recommendedby the manufacturer of the equipment to be used.The systemsmay be of the one component type(same solution for vesseland generator)or the two component type(different solutionfor vessel and generator).Both systems were used in the resultsreported in the App