ASTM_D_926_-_17.pdf

Designation:D92617Standard Test Method forRubber PropertyPlasticity and Recovery(Parallel PlateMethod)1This standard is issued under the fixed designation D926;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the determination of plasticityand recovery of unvulcanized rubber by means of the parallelplate plastometer.Uncompounded,compounded,and reclaimrubber may be tested.NOTE1ISO 2007 and Test Method D3194 use a principle similar tothis test method although the apparatus,test conditions,and procedure aredifferent.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.Referenced Documents2.1 ASTM Standards:2D3194 Test Method for Rubber From Natural SourcesPlasticity Retention Index(PRI)D3767 Practice for RubberMeasurement of DimensionsD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesE145 Specification for Gravity-Convection and Forced-Ventilation Ovens2.2 ISO Standard:3ISO2007 RubberUnvulcanizedDeterminationofPlasticityRapid Plastimeter Method3.Summary of Test Method3.1 Plasticity:3.1.1 A specimen of specific volume and height is tested atroom temperature or heated to a specified test temperature for15 min and then subjected to a compressive force of 49 N fora specified time.3.1.2 At the end of this time,the height of the specimen ismeasured,and the plasticity number is calculated.3.2 RecoveryThere are two recovery procedures.3.2.1 Procedure AThe test specimen is removed from theplastometer immediately after the determination of plasticityand allowed to cool and recover some of its original height for1 min.The height is measured again and the recovery iscalculated.3.2.2 Procedure BThe test specimen is compressed to aheight of 5 mm for 30 s and then allowed to recover at the testtemperature for 5 min.The height is measured again and therecovery is calculated.4.Significance and Use4.1 The plasticity number and the recovery of the testspecimen are related to the flow properties and the elasticproperties,respectively,and may be useful in predictingprocessing characteristics,such as ease of forming and extru-sion characteristics.4.1.1 In this test method,plasticity is measured in an inversemanner,as noted by the final height of the specimen.Thus,high plasticity rubbers(high degree of flow during test)areindicated by a low plasticity number.1This test method is under the jurisdiction of ASTM committee D11 on Rubberand Rubber-like Materials and is the direct responsibility of Subcommittee D11.12in Processability Tests.Current edition approved Oct.1,2017.Published November 2017.Originallyapproved in 1956.Last previous edition approved in 2013 as D926 08(2013).DOI:10.1520/D0926-17.2For 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.3Available from American National Standards Institute,25 West 43rd St.,4thFloor,New York,NY 10036.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 5.Apparatus5.1 The essential features of the parallel plate plastometer,illustrated in Fig.1,are as follows:5.1.1 Two metal plates,not less than 10 mm in thicknessand 40 mm in diameter,shall be mounted on a suitable frameso that one plate moves with respect to the other,and so that thetwo plates are parallel within 0.017 rad(1)at all times.5.1.2 The apparatus shall be so designed that a specimenbetween the parallel plates is subjected to a force of 49 6 0.5N,including the effect of the spring in the d