1、Designation: D1149 15D1149 16Standard 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 yea
2、r 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 These test methods are used
3、 to estimate the effect of exposure, under surface tensile strain conditions, either dynamic orstatic, in an atmosphere containing specified levels of ozone concentration, expressed as partial pressure (refer to Note 1), onvulcanized rubber, rubber compounds, molded or extruded soft rubber, and othe
4、r specified materials, or as may be determinedempirically. The effect of naturally occurring sunlight or light from artificial sources is excluded.1.2 Previously published ASTM documents Test Method D518 and Test Methods D3395 have been included in these testmethods, D1149, in 2007. Please refer to
5、Note 2.1.2.1 Test Method D518 and Test Methods D3395 have henceforth been withdrawn and superseded by Test Methods D1149.When Test Methods D1149 is cited, or otherwise referenced, a notation shall be included to this effect. Please refer to section 3.2for the appropriate references.1.3 The specified
6、 conditions of exposure to ozone in the controlled environments are accelerated in comparison to outdoorexposure. These accelerated ozone test methods may not give results which correlate with outdoor exposure tests or serviceperformance.1.4 All materials, instruments, or equipment used for the dete
7、rmination of mass, force, dimension, ozone concentration, partialpressure, temperature, velocity, and gas exchange rate shall have direct traceability to the National Institute for Standards andTechnology, or other internationally recognized organization parallel in nature.1.5 The values stated in S
8、I units are to be regarded as standard. The values given in parentheses are for information only. Manyof the stated SI units are direct conversions from the U.S. Customary System to accommodate the instrumentation, practices, andprocedures that existed prior to the Metric Conversion Act of 1975.1.6
9、This standard involves hazardous materials, specifically ozone. It may also involve hazardous operations and equipment.This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of theuser of this standard to establish appropriate
10、safety and health practices and determine the applicability of regulatory limitationsprior to use.NOTE 1A discussion and explanation regarding the measurement of ozone concentrations based upon parts of ozone per unit of air versus partialpressure is provided in Test Methods D4575, specifically Appe
11、ndices X1 and X2. Test Methods D4575 is also recommended as a source of backgroundinformation regarding standards involving materials exposed to ozone.2. Referenced Documents2.1 ASTM Standards:2D518 Test Method for Rubber DeteriorationSurface Cracking (Withdrawn 2007)3D1171 Test Method for Rubber De
12、teriorationSurface Ozone Cracking Outdoors (Triangular Specimens)D1349 Practice for RubberStandard Conditions for TestingD3182 Practice for RubberMaterials, Equipment, and Procedures for Mixing Standard Compounds and Preparing StandardVulcanized Sheets1 These test methods are under the jurisdiction
13、of ASTM Committee D11 on Rubber and is the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved July 1, 2015Jan. 1, 2016. Published February 2016. Originally approved in 1951. Last previous edition approved in 20122015 as D1149 07(2012).D1149 15. DOI: 10.1520/D1
14、149-15.10.1520/D1149-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this h
15、istorical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurat
16、ely, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
17、1D3395 Test Methods for Rubber DeteriorationDynamic Ozone Cracking in a Chamber (Withdrawn 2007)3D4482 Test Method for Rubber PropertyExtension Cycling FatigueD4575 Test Methods for Rubber DeteriorationReference and Alternative Method(s) for Determining Ozone Level inLaboratory Test ChambersNOTE 2Te
18、st Method D518 and Test Methods D3395 have been incorporated into these test methods. They remain technically unchanged and willbe superseded by Test Methods D 1149. Please refer to Test Method D1171 for tests which are to be performed outdoors.3. Summary of Test Methods3.1 There are two methods des
19、cribed:3.1.1 Method ADynamic Strain (formerly Test Methods D3395):3.1.1.1 Method A, Procedure A1 Dynamic Tensile Elongation (formerly Test Methods D3395 Method A)rectangular testspecimens are subjected to dynamic maximum amplitude tensile strain of 25 6 3 % at a fixed frequency of 0.5 Hz (30 cpm).3.
20、1.1.2 Method A, Procedure A2 Dynamic Belt Flex Test (formerly Test Methods D3395 Method B)rectangular test specimensare affixed to a fabric belt which is continuously rotated over two vertically opposed pulleys that induce a cyclical surface strain(due to flexing) during the moments of passage over
21、the pulleys.3.1.2 Method BStatic Strain (formerly Test Method D518):3.1.2.1 Method B, Procedure B1 Static Strain (formerly Test Method D518, Method A)rectangular specimens are exposed toa continuous elongation of 20 %.3.1.2.2 Method B, Procedure B2 Static Strain Looped Specimen Test (formerly Test M
22、ethod D518, Method B)rectangularspecimens are mounted, in a looped fashion, causing a continuous strain to be applied on the looped portion.3.1.2.3 Method B, Procedure B3 Static Percent Elongation Test (formerly Test Method D518, Method C)tapered specimensare exposed to specified percentages of elon
23、gation (10, 15, and 20 %) during the course of exposure.3.1.2.4 Method B, Procedure B4 Static Strain Triangular Specimen (formerly Test Method D1171)triangular specimens aremounted around a wooden mandrel causing a continuous strain to be applied to the looped portion.(1) Method B, Procedure B4-A Ex
24、posure Rating (formerly Test Method D1171 Method A).(2) Method B, Procedure B4-B Quality Retention Rating (formerly Test Method D1171 Method B).3.2 The Procedures appear as follows:ProcedureDescription SectionsA1Dynamic TensileElongation7 10 (formerly D3395 Method A)A2Dynamic Belt Flex 11 14 (former
25、ly D3395 Method B)B1Straight Specimens(Static Elongation)15 17/24 (formerly D518/D 1149 MethodA)B2Bent Loop Specimen 18 20/24 (formerly D518/D 1149 MethodB)B3Tapered Specimens(Static Elongation)21 23/24 (formerly D518/D 1149 MethodC)B4-ATriangular Speci-mens24 (formerly D1171 Method A ExposureRating
26、)B4-BTriangular Speci-mens24 (formerly D1171 Method B Quality Re-tention Rating)4. Significance and Use4.1 The significance of these test methods lies in the ability to differentiate between the degrees of ozone resistance under thelimited and specified conditions of the accelerated tests. The degre
27、e of resistance being judged by the appearance and magnitudeof the formation of cracks in the surface of the subject material.4.2 In service, rubber materials deteriorate when exposed to ozone. It is imperative to have test methods in which simple,accelerated time/exposure, comparisons of the materi
28、als ability to resist cracking caused by ozone exposure can be empiricallyevaluated. Such tests can be used for producer/consumer acceptance, referee purposes, research, and development.4.3 These methods are not necessarily suited for use in purchase specifications as there may be no correlation wit
29、h serviceperformance as actual service conditions (outdoor exposure) vary widely due to geographic location and, therefore, may not yieldrepeatable or reproducible results.5. Apparatus5.1 The apparatus employed to provide a controlled environment containing specified concentrations of ozone and part
30、ialpressures, at specified temperatures, is described in 5.2, being common to all test methods enumerated herein. The ancillaryequipment required to perform individual procedures is described in their respective sections.5.2 Ozone Test Apparatus:5.2.1 Test ChamberGeneral requirements for an acceptab
31、le ozone test chamber are adequate control and measurement ofozone concentration levels based upon partial pressure (refer to Note 1); volume exchange rate; temperature; internal chamberD1149 162circulation of the gas (airozone mixture, refer to Note 3); and internal chamber volume. An acceptable oz
32、one test chamber maybe individually manufactured for a particular application, or a commercially manufactured chamber. The ozone test chambers shallconform to the following requirements:NOTE 3Daltons Law and the gas equation is used to express ozone content as partial pressure. The partial pressure
33、of ozone in a mixture with air,P(O3), is given in millipascals (mPa).5.2.1.1 The internal chamber shall be constructed of a material with minimal reaction to ozone, preferably stainless steel,contained within an integral external structure which provide unencumbered access to the mechanical, electri
34、cal, display, andcontrol devices.(1) The internal chamber shall be accessible through a door having an adequate closure mechanism and seal to prevent lossof partial pressure or adversely affect the ozone concentration levels throughout the duration of a test. It is recommended that thedoor have a me
35、ans by which to prevent inadvertent opening during the intended duration of a test.(2) The access door may be equipped with an observation window. This shall be of tempered glass and shall be sealed toprevent loss of partial pressure or adversely affect the ozone concentration level throughout the d
36、uration of a test.(3) The internal chamber may be equipped with a source of illumination. It shall be situated in a manner so that neither thetemperature of the internal chamber, the ozone concentration level, or partial pressure is adversely affected. Illumination is to beused in a temporary fashio
37、n, intended for intermediate viewing of the specimens. Long term use, in excess of a consecutive 5-minperiod, or more than a total of 15 min, during any given 24-h period, invalidates determinations and therefore requires monitoringand reporting.(4) The internal chamber may be equipped with shelves,
38、 or racks, on which to place specimens. They shall be constructed ofa material with minimal reaction to ozone, preferably stainless steel. They shall be of a design that minimizes the effect on theintroduction, circulation, exchange, or exhaust of the gas (airozone mixture).5.2.1.2 The internal volu
39、me of the chamber shall be no less than 0.11 m (4 ft3). The internal chamber volume may be greater,provided the prescribed levels of ozone concentration and partial pressure are maintained (refer to 5.2.1.3(1) and Note 1).5.2.1.3 A means for generating, measuring, and controlling ozone concentration
40、s levels and partial pressure shall be provided.The ozone generating source shall be isolated from the internal chamber and within the integral external structure.(1) The generation and introduction of ozone shall be by a means whereby ozone concentration levels in the internal testchamber of betwee
41、n 25 and 200 pphm (parts per hundred million) 6 10 % at 100 kPa (atmospheric pressure at mean sea level,MSL) and the equivalent pressures of between 25 and 200 mPa 6 10 % are maintained throughout the duration of the test (referto Notes 1 and 2).The preferred method of ozone generation being either
42、quartz UV, corona discharge (dielectric), or a combinationof both.(2) The test chamber ozone concentration levels and pressures shall be either infinitely variable between those prescribed or,at minimum, selectable at 25, 50, 100, 200 pphm and mPa, respectively. Broader ranges of ozone concentration
43、 and partial pressureare acceptable, provided the specified concentrations of ozone and partial pressure are maintained as specified.(3) The means of measurement of the ozone concentration shall be by any of the methods described in Test Methods D4575,with ultraviolet (UV) absorption measurement bei
44、ng preferred as it has been shown to be more accurate and precise.5.2.1.4 The source of air may be ambient, or from a compressed air supply. In either case, adequate filtration of particulatematter from the source shall be provided. The moisture content of the air source shall be minimized, either t
45、hrough filtration, adesiccant, or by other means.5.2.1.5 The flow of the gases (air and ozone) shall be introduced into the chamber in a manner that prevents stratification orstagnation.5.2.1.6 The gas (airozone mixture) exchange rate shall be of a magnitude such that no appreciable reduction in ozo
46、neconcentration or partial pressure results from the introduction of test specimens.(1) The exchange rate will vary with the gas (airozone mixture) level, temperature, number of test specimens introduced, andtheir reaction with ozone.(2) A gas (airozone mixture) exchange rate of 75 % of the total vo
47、lume of the internal chamber per minute has been foundto be an acceptable and adequate rate, and shall be considered to be the minimum acceptable rate of gas exchange.(3) As indicated, this exchange rate will vary, dependent upon the enumerated variables, and the minimum exchange rate shallbe establ
48、ished locally, as agreed upon between customer and supplier, or between laboratories, but shall not be less than thatdescribed in 5.2.1.6(2).5.2.1.7 A means of providing internal chamber circulation of the gas (airozone mixture) shall be provided by an electric fancapable of maintaining a constant v
49、elocity throughout the duration of a test. The velocity shall be no less than 0.6 m/s (2 fts) asmeasured at 50 6 1 mm (1.97 6 0.04 in.) from the forward edge of the fan blades on the internal side of the chamber.(1) The fan motor shall not be located within the internal chamber. The fan motor shall employ an extension shaft, or drivemechanism, that isolates the motor from the internal chamber with an ozone resistant seal that assures the integrity of separationbetween the motor and the internal chamber.(2) The fan blades shall be re
