ASTM_D_865_-_11.pdf

Designation:D86511Standard Test Method forRubberDeterioration by Heating in Air(Test TubeEnclosure)1This standard is issued under the fixed designation D865;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 a procedure to determine thedeterioration induced by heating rubber specimens in indi-vidual test tube enclosures with circulating air.This isolationprevents cross contamination of compounds due to loss ofvolatile materials(for example,antioxidants)and their subse-quent migration into other rubber compounds(specimens).Theabsorption of such volatile materials may influence the degra-dation rate of rubber compounds.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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:2D412 Test Methods for Vulcanized Rubber and Thermoplas-tic ElastomersTensionD573 Test Method for RubberDeterioration in an AirOvenD1349 Practice for RubberStandard Conditions for Test-ingD2240 Test Method for Rubber PropertyDurometer Hard-nessD3182 Practice for RubberMaterials,Equipment,and Pro-cedures for Mixing Standard Compounds and PreparingStandard Vulcanized SheetsD3183 Practice for RubberPreparation of Pieces for TestPurposes from ProductsD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3.Summary of Test Methods3.1 Specimens of vulcanized rubber are exposed to thedeteriorating influence of air at specified elevated temperaturefor known periods of time,after which their physical propertiesare determined.These are compared with the properties deter-mined on the original unexposed specimens and the changesnoted.3.2 Unless otherwise specified,the determination of thephysical properties shall be carried out in accordance with testmethods in Test Methods D412.3.3 Except as may be otherwise specified in this testmethod,the requirements of Practices D3182 and D3183 shallbe complied with and are made part of this test method.3.4 In case of conflict between the provisions of this testmethod and those of detailed specifications or test methods fora particular material,the latter shall take precedence or ifotherwise agreed upon between customer and supplier orbetween laboratories.4.Significance and Use4.1 Rubber and rubber products must resist the deteriorationof physical properties with time caused by oxidative andthermal ageing.This test method determines these character-istics in a way that is free of some of the complications inherentin community-type ageing devices,that is where numerouscompounds(specimens)are aged in the same enclosure.4.2 The isolation of compounds(specimens)by the use ofindividual circulating air test tube enclosures prevents crosscontamination from volatile products and permits a morerepresentative assessment of ageing performance.4.3 Please refer to the Annex in Test Method D573 forimportant information on standard compounds used for preci-sion testing for accelerated test ageing evaluation.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved Aug.15,2011.Published September 2011.Originallyapproved in 1946.Last previous edition approved in 2005 as D865 99(2005).DOI:10.1520/D0865-11.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Apparatus5.1 The apparatus for heat ageing shall consist of borosili-cate glass test tubes 38 mm(1.52 in.)in diameter and 300 mm(12 in.)in length heated uniformly in suitable equipment suchas an oil or water bath or metal block(see Fig.1)so arrangedas to comply with the following requirements:5.1.1 No more than three specimens shall be exposed ineach test tube,and all specimens in a single tube shall be froma single compound.5.1.2 Provisions shall be made for vertical suspension of thespecimens as near the bottom of the test tube as possiblewithout touching each other or the sides of the test tube duringthe test.Asuggested means for holding the specimens is shownin Fig.2.5