ASTM_D_8300_-_19.pdf

Designation:D830019Standard Test Method forSilica,Precipitated,HydratedElectrical Conductivity1This standard is issued under the fixed designation D8300;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 is used to determine the electricalconductivity of silica and the electrical conductivity is suitablefor characterizing rubber-grade silicas.1.2 UnitsThe values stated in SI units are to be regardedas the standard.No other units of measurement are included inthis standard.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.Summary of Test Method2.1 The adsorption of water on the silica surface enhancesits electrical conductivity.Different mechanisms,both elec-tronic and ionic,can cause this effect.2.2 This standard test method provides a procedure for thedetermination of the electrical conductivity in an aqueoussuspension of silica.3.Significance and Use3.1 The electrical conductivity of silica is related to both theadsorbed water and the hydroxyl groups on the surface of theprecipitated,hydrated silica.Since the electrical conductivityof distilled or de-ionized water is very low,high electricalconductivity values are associated with ionic sources due toimpurities.3.2 A specific quantity of the silica sample is boiled indistilled or deionized water.After cooling to room temperature,the suspension is diluted to 4%mass per volume(m/V)and itstemperature is adjusted to 20C with a thermostat.The elec-trical conductivity is measured using a conductivity meter anda conductivity cell.4.Apparatus4.1 Precision Balance,0.01 g sensitivity.4.2 Beaker,glass,50 cm3.4.3 Beaker,glass,150 cm3.4.4 Conductivity Meter,equipped with a conductivity cell.4.5 Lab Thermostat.4.6 Laboratory Grinder,or,alternatively,mortar and pestle.4.7 Magnetic Stirrer,with stir bar.4.8 Funnel.4.9 Volumetric Flask,100 cm3.4.10 Watch Glass.4.11 Graduated Cylinder,glass,100 cm3.5.Reagents and Materials5.1 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 wheresuch specifications are available.2Other 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.5.2 Specific Reagents:5.2.1 Potassium chloride solution(0.0100 6 0.0001)mol/LDry an appropriate amount of KCl in an oven for approxi-mately 1 h at(105 6 2)C and cool it to ambient temperaturein a desiccator.Weigh(0.7455 6 0.0005)g of the driedsubstance and transfer it with deionized water into a 1 Lgraduated flask.After dissolution of the salt,fill up the flaskwith deionized water.Ensure that the flask is filled up to the1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand Rubber-like Materials and is the direct responsibility of Subcommittee D11.20on Compounding Materials and Procedures.Current edition approved Nov.1,2019.Published November 2019.DOI:10.1520/D8300-19.2ACS Reagent Chemicals,Specifications and Procedures for Reagents andStandard-Grade Reference Materials,American Chemical Society,Washington,DC.For suggestions on the testing of reagents not listed by the American ChemicalSociety,see Analar Standards for Laboratory Chemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeia and National Formulary,U.S.Pharma-copeial Convention,Inc.(USPC),Rockville,MD.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 mark after adjusting the temperature to(20.0 6 0.5)C andthat the solution is well homogenized.KCl solutions with theconcentration needed for this test method are commerciallyavailable.5.2.2 Deionized or distilled water,conductivity 10 S/cm,thecell constant must be adjusted to the nomin