ASTM_D_6048_-_07_2018.pdf

Designation:D604807(Reapproved 2018)Standard Practice forStress Relaxation Testing of Raw Rubber,UnvulcanizedRubber Compounds,and Thermoplastic Elastomers1This standard is issued under the fixed designation D6048;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.INTRODUCTIONThere are a number of techniques used to identify the processability of raw rubber,unvulcanizedrubber compounds,and thermoplastic elastomers(rubber and rubberlike materials).Most measure asingle averaged value of non-Newtonian viscosity with some doing so after a period of steady shear.These techniques may not provide sufficient information with regards to the processability of aselected material,as they:(1)fail to provide a measure of the viscoelastic behavior,and(2)destroystructure of the selected material through the steady shearing.Stress relaxation testing provides a measure of the viscoelastic response of a material over a periodof time without destroying the structure of the sample.In such testing both the instantaneous andtime-dependent response to an applied deformation are measured.The information from this singleexperiment can then be used to examine a materials reaction to various different process conditions.There are several different techniques for measuring stress relaxation properties of rubber andrubberlike materials.This practice serves to provide the reader with some background informationabout those techniques in terms of the theory of testing and the interpretation of results.Manyconcepts are put forward that are not discussed in depth,for to do so would require a textbook,nota practice.The reader is therefore encouraged to consult the identified references.1.Scope1.1 This practice covers several different techniques fordetermining the stress relaxation characteristics of rubber andrubberlike materials and for the possible interconversion of thisstress relaxation information into dynamic mechanical proper-ties.1.2 The techniques are intended for materials having stressrelaxation moduli in the range of 103to 108Pa(0.1 to 1.5 104psi)and for test temperatures from 23 to 225C(73 to 437F).Not all measuring apparatus may be able to accommodate theentire ranges.These techniques are also intended for measure-ment of materials in their rubbery or molten states,or both.1.3 Differences in results will be found among the tech-niques.Because of these differences,the test report needs toinclude the technique and the conditions of the test.Thisinformation will allow for resolving any issues pertaining tothe test measurements.1.4 The generalized descriptions of apparatus are based onthe measurement of force as a function of time.Mathematicaltreatment of that relationship produces information that can berepresentative of material properties.Mathematical transfor-mation of the force measurements will first yield stressrelaxation moduli with subsequent transformation producingdynamic mechanical properties.1.5 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are provided forinformation only.1.6 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.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for the1This practice is under the jurisdiction of Committee D11 on Rubber andRubber-like Materials and is the direct responsibility of Subcommittee D11.12 onProcessability Tests.Current edition approved Sept.1,2018.Published November 2018.Originallyapproved in 1996.Last previous edition approved in 2012 as D6048 07(2012).DOI:10.1520/D6048-07R18.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 Development of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1566 Terminology Relating to RubberD1646 TestMethodsforRubberViscosity,StressRelaxation,andPre-VulcanizationCharacteristics(Mooney Viscometer)D5992 Guide for Dynamic Testing of Vulcanized Rubberand Rubber-Like Materials Using Vibratory MethodsE328 Test Methods for Stre