ASTM_D_7854_-_15.pdf

Designation:D785415Standard Test Method forCarbon Black-Void Volume at Mean Pressure1This standard is issued under the fixed designation D7854;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 procedure to measure a carbonblack structure property known as Void Volume at meanpressure.Compressed void volumes are obtained by measuringthe compressed volume of a weighed sample in a cylindricalchamber as a function of pressure exerted by a movable piston.A profile of void volume as a function of pressure provides ameans to assess carbon black structure at varying levels ofdensity and aggregate reduction.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:2D1799 Practice for Carbon BlackSampling PackagedShipmentsD1900 Practice for Carbon BlackSampling Bulk Ship-mentsD2414 Test Method for Carbon BlackOil AbsorptionNumber(OAN)D3493 Test Method for Carbon BlackOil AbsorptionNumber of Compressed Sample(COAN)D4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesD4821 Guide for Carbon BlackValidation of Test MethodPrecision and BiasD6086 Test Method for Carbon BlackVoid Volume(VV)(Withdrawn 2015)33.Terminology3.1 Refer to Sections 4 and 9 for a more complete under-standing of the use of these terms in this test method.3.2 Definitions of Terms Specific to This Standard:3.2.1 applied pressure,nthe pressure exerted on a samplemass by a movable piston in a cylindrical chamber,where theload cell or force measuring system is in contact with themovable piston.3.2.2 compressed volume(carbon black),nthe apparentvolume that a specified mass of carbon black occupies when itis contained in a specified cylindrical chamber and subjected toa single uniaxial compression at a specified pressure by meansof a movable piston.3.2.3 geometric mean pressure,nthe geometric mean ofthe applied and transmitted pressures at a specific void volume;the geometric mean pressure is defined in Eq 1:Geometric Mean PGM5Pa3 Pt!0.5(1)3.2.4 theoretical volume(carbon black),nthe volume thata specific mass of carbon black would occupy if there were novoid space within the carbon black,and is given by the ratio ofmass to skeletal density,where the skeletal density is deter-mined by an accepted test method.3.2.5 transmitted pressure,nthe resulting pressure trans-mitted through a sample in a cylindrical chamber,where theload cell or force measuring system is in contact with thesample opposite the movable piston,typically via a stationarysecond piston.3.2.6 void volume(carbon black),na measure of theintra-aggregate void space or occluded volume within theprimary structure of carbon black,characterized by the irregu-larity and non-sphericity of carbon black aggregate particles,and expressed as the difference(compressed volume minustheoretical volume)as a function of specified uniaxial com-pression pressure,and normalized to 100 g mass.3.2.6.1 DiscussionCarbonblacksresistpacking,compression,and fracture due to aggregate irregularities and1This test method is under the jurisdiction of ASTM Committee D24 on CarbonBlack and is the direct responsibility of Subcommittee D24.11 on Carbon BlackStructure.Current edition approved June 1,2015.Published September 2015.Originallyapproved in 2013.Last previous edition approved in 2013 as D7854 13.DOI:10.1520/D7854-15.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 entanglements,size distribution,and aggregate strength result-ing from particle to-particle necks within aggregate branches.Compressed void volume is also affected by reacting forces tothe cylinder wall and the piston tip,which in turn depend onfactors including sample shape(that is,the ratio of sampleheight to cylinder diameter)or interfacial area,which caninfluence the uniformity of the compaction density.Sincecompressed void volumes as a function of applied pressure areknown to be specific to sample mass and cylinder geometry,such a compressed void volume is biased due