1、Designation: D1149 18Standard Test Methods forRubber DeteriorationCracking in an Ozone ControlledEnvironment1This standard is issued under the fixed designation D1149; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 These test methods are used to esti
3、mate the effect ofexposure, under surface tensile strain conditions, either dy-namic or static, in an atmosphere containing specified levels ofozone concentration, expressed as partial pressure (refer toNote 1), on vulcanized rubber, rubber compounds, molded orextruded soft rubber, and other specifi
4、ed materials, or as maybe determined empirically. The effect of naturally occurringsunlight or light from artificial sources is excluded.1.2 Previously published ASTM documents Test MethodD518 andTest Methods D3395 have been included in these testmethods, D1149, in 2007. Please refer to Note 2.1.2.1
5、 Test Method D518 and Test Methods D3395 havehenceforth been withdrawn and superseded by Test MethodsD1149. When Test Methods D1149 is cited, or otherwisereferenced, a notation shall be included to this effect. Pleaserefer to section 3.2 for the appropriate references.1.3 The specified conditions of
6、 exposure to ozone in thecontrolled environments are accelerated in comparison tooutdoor exposure. These accelerated ozone test methods maynot give results which correlate with outdoor exposure tests orservice performance.1.4 All materials, instruments, or equipment used for thedetermination of mass
7、, force, dimension, ozone concentration,partial pressure, temperature, velocity, and gas exchange rateshall have direct traceability to the National Institute forStandards and Technology, or other internationally recognizedorganization parallel in nature.1.5 The values stated in SI units are to be r
8、egarded asstandard. The values given in parentheses are for informationonly. Many of the stated SI units are direct conversions fromthe U.S. Customary System to accommodate theinstrumentation, practices, and procedures that existed prior tothe Metric Conversion Act of 1975.1.6 This standard involves
9、 hazardous materials, specificallyozone. It may also involve hazardous operations and equip-ment. 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 e
10、nvironmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE 1A discussion and explanation regarding the measurement ofozone concentrations based upon parts of ozone per unit of air versuspartial pressure is provided in Test Methods D4575, specifically Appen-di
11、ces X1 and X2. Test Methods D4575 is also recommended as a sourceof background information regarding standards involving materials ex-posed to ozone.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision
12、 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:2D518 Test Method for Rubber DeteriorationSurfaceCracking (Withdrawn 2007)3D1171 Test
13、Method for Rubber DeteriorationSurfaceOzone Cracking Outdoors (Triangular Specimens)D1349 Practice for RubberStandard Conditions for Test-ingD3182 Practice for RubberMaterials, Equipment, and Pro-cedures for Mixing Standard Compounds and PreparingStandard Vulcanized SheetsD3395 Test Methods for Rubb
14、er DeteriorationDynamicOzone Cracking in a Chamber (Withdrawn 2007)31These test methods are under the jurisdiction of ASTM Committee D11 onRubber and Rubber-like Materials and are the direct responsibility of SubcommitteeD11.15 on Degradation Tests.Current edition approved June 1, 2018. Published Se
15、ptember 2018. Originallyapproved in 1951. Last previous edition approved in 2016 as D1149 16. DOI:10.1520/D1149-18.2For 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 t
16、he 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 StatesThis international standard was developed in acco
17、rdance 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.1D4482 Test Method for Rubber Pr
18、opertyExtension Cy-cling FatigueD4575 Test Methods for Rubber DeteriorationReferenceand Alternative Method(s) for Determining Ozone Levelin Laboratory Test ChambersNOTE 2Test Method D518 and Test Methods D3395 have beenincorporated into these test methods. They remain technically unchangedand will b
19、e superseded by Test Methods D 1149. Please refer to TestMethod D1171 for tests which are to be performed outdoors.3. Summary of Test Methods3.1 There are two methods described:3.1.1 Method ADynamic Strain (formerly Test MethodsD3395):3.1.1.1 Method A, Procedure A1 Dynamic Tensile Elonga-tion (forme
20、rly Test Methods D3395 Method A)rectangulartest specimens are subjected to dynamic maximum amplitudetensile strain of 25 6 3 % at a fixed frequency of 0.5 Hz (30cpm).3.1.1.2 Method A, Procedure A2 Dynamic Belt Flex Test(formerly Test Methods D3395 Method B)rectangular testspecimens are affixed to a
21、fabric belt which is continuouslyrotated over two vertically opposed pulleys that induce acyclical surface strain (due to flexing) during the moments ofpassage over the pulleys.3.1.2 Method BStatic Strain (formerly Test MethodD518):3.1.2.1 Method B, Procedure B1 Static Strain (formerly TestMethod D5
22、18, Method A)rectangular specimens are exposedto a continuous elongation of 20 %.3.1.2.2 Method B, Procedure B2 Static Strain Looped Speci-men Test (formerly Test Method D518, Method B)rectangularspecimens are mounted, in a looped fashion, causing a con-tinuous strain to be applied on the looped por
23、tion.3.1.2.3 Method B, Procedure B3 Static Percent ElongationTest (formerly Test Method D518, Method C)tapered speci-mens are exposed to specified percentages of elongation (10,15, and 20 %) during the course of exposure.3.1.2.4 Method B, Procedure B4 Static Strain TriangularSpecimen (formerly Test
24、Method D1171)triangular speci-mens are mounted around a wooden mandrel causing acontinuous strain to be applied to the looped portion.(1) Method B, Procedure B4-A Exposure Rating (formerlyTest Method D1171 Method A).(2) Method B, Procedure B4-B Quality Retention Rating(formerly Test Method D1171 Met
25、hod B).3.2 The Procedures appear as follows:ProcedureDescription SectionsA1Dynamic TensileElongation710(formerly D3395 Method A)A2Dynamic Belt Flex 1114(formerly D3395 Method B)B1Straight Specimens(Static Elongation)1517/24 (formerly D518/D 1149 MethodA)B2Bent Loop Specimen 1820/24 (formerly D518/D
26、1149 MethodB)B3Tapered Specimens(Static Elongation)2123/24 (formerly D518/D 1149 MethodC)B4Triangular Speci-mens27 (formerly D1171 Static Strain)B4-ATriangular Speci-mens27 (formerly D1171 Method A ExposureRating)B4-BTriangular Speci-mens27 (formerly D1171 Method B Quality Re-tention Rating)4. Signi
27、ficance and Use4.1 The significance of these test methods lies in the abilityto differentiate between the degrees of ozone resistance underthe limited and specified conditions of the accelerated tests.The degree of resistance being judged by the appearance andmagnitude of the formation of cracks in
28、the surface of thesubject material.4.2 In service, rubber materials deteriorate when exposed toozone. It is imperative to have test methods in which simple,accelerated time/exposure, comparisons of the materials abil-ity to resist cracking caused by ozone exposure can beempirically evaluated. Such t
29、ests can be used for producer/consumer acceptance, referee purposes, research, and develop-ment.4.3 These methods are not necessarily suited for use inpurchase specifications as there may be no correlation withservice performance as actual service conditions (outdoorexposure) vary widely due to geog
30、raphic location and,therefore, may not yield repeatable or reproducible results.5. Apparatus5.1 The apparatus employed to provide a controlled envi-ronment containing specified concentrations of ozone andpartial pressures, at specified temperatures, is described in 5.2,being common to all test metho
31、ds enumerated herein. Theancillary equipment required to perform individual proceduresis described in their respective sections.5.2 Ozone Test Apparatus:5.2.1 Test ChamberGeneral requirements for an accept-able ozone test chamber are adequate control and measurementof ozone concentration levels base
32、d upon partial pressure (referto Note 1); volume exchange rate; temperature; internal cham-ber circulation of the gas (airozone mixture, refer to Note 3);D1149 182and internal chamber volume. An acceptable ozone test cham-ber may be individually manufactured for a particularapplication, or a commerc
33、ially manufactured chamber. Theozone test chambers shall conform to the following require-ments:NOTE 3Daltons Law and the gas equation is used to express ozonecontent as partial pressure. The partial pressure of ozone in a mixture withair, P(O3), is given in millipascals (mPa).5.2.1.1 The internal c
34、hamber shall be constructed of amaterial with minimal reaction to ozone, preferably stainlesssteel, contained within an integral external structure whichprovide unencumbered access to the mechanical, electrical,display, and control devices.(1) The internal chamber shall be accessible through a doorh
35、aving an adequate closure mechanism and seal to prevent lossof partial pressure or adversely affect the ozone concentrationlevels throughout the duration of a test. It is recommended thatthe door have a means by which to prevent inadvertent openingduring the intended duration of a test.(2) The acces
36、s door may be equipped with an observationwindow. This shall be of tempered glass and shall be sealed toprevent loss of partial pressure or adversely affect the ozoneconcentration level throughout the duration of a test.(3) The internal chamber may be equipped with a source ofillumination. It shall
37、be situated in a manner so that neither thetemperature of the internal chamber, the ozone concentrationlevel, or partial pressure is adversely affected. Illumination is tobe used in a temporary fashion, intended for intermediateviewing of the specimens. Long term use, in excess of aconsecutive 5-min
38、 period, or more than a total of 15 min,during any given 24-h period, invalidates determinations andtherefore requires monitoring and reporting.(4) The internal chamber may be equipped with shelves, orracks, on which to place specimens. They shall be constructedof a material with minimal reaction to
39、 ozone, preferablystainless steel. They shall be of a design that minimizes theeffect on the introduction, circulation, exchange, or exhaust ofthe gas (airozone mixture).5.2.1.2 The internal volume of the chamber shall be no lessthan 0.11 m (4 ft3). The internal chamber volume may begreater, provide
40、d the prescribed levels of ozone concentrationand partial pressure are maintained (refer to 5.2.1.3(1) andNote 1).5.2.1.3 A means for generating, measuring, and controllingozone concentrations levels and partial pressure shall beprovided. The ozone generating source shall be isolated fromthe interna
41、l chamber and within the integral external structure.(1) The generation and introduction of ozone shall be by ameans whereby ozone concentration levels in the internal testchamber of between 25 and 200 pphm (parts per hundredmillion) 6 10 % at 100 kPa (atmospheric pressure at mean sealevel, MSL) and
42、 the equivalent pressures of between 25 and200 mPa 6 10 % are maintained throughout the duration of thetest (refer to Notes 1 and 2). The preferred method of ozonegeneration being either quartz UV, corona discharge(dielectric), or a combination of both.(2) The test chamber ozone concentration levels
43、 and pres-sures shall be either infinitely variable between those pre-scribed or, at minimum, selectable at 25, 50, 100, 200 pphmand mPa, respectively. Broader ranges of ozone concentrationand partial pressure are acceptable, provided the specifiedconcentrations of ozone and partial pressure are mai
44、ntained asspecified.(3) The means of measurement of the ozone concentrationshall be by any of the methods described in Test MethodsD4575, with ultraviolet (UV) absorption measurement beingpreferred as it has been shown to be more accurate and precise.5.2.1.4 The source of air may be ambient, or from
45、 acompressed air supply. In either case, adequate filtration ofparticulate matter from the source shall be provided. Themoisture content of the air source shall be minimized, eitherthrough filtration, a desiccant, or by other means.5.2.1.5 The flow of the gases (air and ozone) shall beintroduced int
46、o the chamber in a manner that prevents strati-fication or stagnation.5.2.1.6 The gas (airozone mixture) exchange rate shall beof a magnitude such that no appreciable reduction in ozoneconcentration or partial pressure results from the introductionof test specimens.(1) The exchange rate will vary wi
47、th the gas (airozonemixture) level, temperature, number of test specimensintroduced, and their reaction with ozone.(2) Agas (airozone mixture) exchange rate of 75 % of thetotal volume of the internal chamber per minute has been foundto be an acceptable and adequate rate, and shall be consideredto be
48、 the minimum acceptable rate of gas exchange.(3) As indicated, this exchange rate will vary, dependentupon the enumerated variables, and the minimum exchangerate shall be established locally, as agreed upon betweencustomer and supplier, or between laboratories, but shall not beless than that describ
49、ed in 5.2.1.6(2).5.2.1.7 A means of providing internal chamber circulationof the gas (airozone mixture) shall be provided by an electricfan capable of maintaining a constant velocity throughout theduration of a test. The velocity shall be no less than 0.6 m/s(2 fts) as measured at 50 6 1 mm (1.97 6 0.04 in.) from theforward edge of the fan blades on the internal side of thechamber.(1) The fan motor shall not be located within the internalchamber. The fan motor shall employ an extension shaft, ordrive mechanism, that isolates the motor from
