1、Designation: D1149 07 (Reapproved 2012)D1149 15Standard 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
2、 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 These tes
3、t methods are used 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 sof
4、t rubber, and other 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
5、. Please refer to Note 2.1.2.1 Test Method D518 and Test Methods D3395 have henceforth been withdrawn and superseded by Test Methods D1149.When Test Methods D1149 is cited, or otherwise referenced, a notation shall be included to this effect.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
6、.1.3 The specified 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
7、 used for the determination 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
8、values stated in SI 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 Conversio
9、n Act of 1975.1.6 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 esta
10、blish appropriate 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,
11、 specifically Appendices 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 Me
12、thod for Rubber DeteriorationSurface 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
13、 the jurisdiction of ASTM Committee D11 on Rubber and is the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved May 1, 2012July 1, 2015. Published May 2012February 2016. Originally approved in 1951. Last previous edition approved in 20072012 asD1149 07.D1149 0
14、7 (2012). DOI: 10.1520/D1149-07R12.10.1520/D1149-15.2 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 las
15、t approved version of this historical 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 adequatel
16、y depict all changes accurately, 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,
17、PA 19428-2959. United States1D3395 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 inLabo
18、ratory Test ChambersNOTE 2Test 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 Test Method D518tests which are to be performed outdoors.3. Summary
19、of Test Methods3.1 There are two methods described: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
20、% at a fixed frequency of 0.5 Hz (30 cpm).3.1.1.2 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
21、flexing) during the moments of passage over 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
22、Strain Looped Specimen Test (formerly Test Method 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 specimens
23、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 Triangular Specimen (formerly Test Method D1171)triangular specimens aremounted around a wooden mandrel causing a continuous strain to be applied to the lo
24、oped portion.(1) Method B, Procedure B4-A Exposure 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 D339
25、5 Method A)A2Dynamic Belt Flex 11 14 (formerly 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)B4Triangular Speci-mens
26、24 and 24 (formerly D1171)B4-ATriangular Speci-mens24 (formerly D1171 Method A ExposureRating)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 o
27、zone resistance under thelimited and specified conditions of the accelerated tests. The degree 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 imperat
28、ive to have test methods in which simple,accelerated time/exposure, comparisons of the materials 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
29、 not necessarily suited for use in purchase specifications as there may be no correlation with 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 emplo
30、yed to provide a controlled environment containing specified concentrations of ozone and partialpressures, 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 respec
31、tive sections.5.2 Ozone Test Apparatus:D1149 1525.2.1 Test ChamberGeneral requirements for an acceptable ozone test chamber are adequate control and measurement ofozone concentration levels based upon partial pressure (refer to Note 1); volume exchange rate; temperature; internal chambercirculation
32、of the gas (airozone mixture, refer to Note 3); and internal chamber volume. An acceptable ozone 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
33、 the gas equation is used to express ozone content as partial pressure. The partial pressure 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 withi
34、n an integral external structure which provide unencumbered access to the mechanical, electrical, 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 con
35、centration levels throughout the duration of a test. It is recommended that thedoor have a means 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 topreven
36、t loss of partial pressure or adversely affect the ozone concentration level throughout the duration 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 leve
37、l, or partial pressure is adversely affected. Illumination is to beused in a temporary fashion, 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 ther
38、efore requires monitoringand reporting.(4) The internal chamber may be equipped with shelves, 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 theintroducti
39、on, circulation, exchange, or exhaust of the gas (airozone mixture).5.2.1.2 The internal volume 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(
40、1) and Note 1).5.2.1.3 A means for generating, measuring, and controlling ozone concentrations 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
41、 shall be by a means whereby ozone concentration levels in the internal testchamber of between 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 durati
42、on of the test (referto Notes 1 and 2).The preferred method of ozone generation being either 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, sel
43、ectable at 25, 50, 100, 200 pphm and mPa, respectively. Broader ranges of ozone concentration 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
44、 the methods described in Test Methods D4575,with ultraviolet (UV) absorption measurement being 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
45、source shall be provided. The moisture content of the air source shall be minimized, either through 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 (airo
46、zone mixture) exchange rate shall be of a magnitude such that no appreciable reduction in ozoneconcentration 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, an
47、dtheir reaction with ozone.(2) A gas (airozone mixture) exchange rate of 75 % of the total volume 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 wil
48、l vary, dependent upon the enumerated variables, and the minimum exchange rate shallbe established 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 g
49、as (airozone mixture) shall be provided by an electric fancapable of maintaining a constant velocity 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 in
