1、Designation: D 573 04Standard Test Method forRubberDeterioration in an Air Oven1This standard is issued under the fixed designation D 573; 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 paren
2、theses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers a procedure to determine theinfluence of ele
3、vated temperature on the physical properties ofvulcanized rubber. The results of this test method may not givean exact correlation with service performance since perfor-mance conditions vary widely. This test method may, however,be used to evaluate rubber compounds on a laboratory com-parison basis.
4、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 app
5、ro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. (For specificprecautionary statement, see Note 1.)2. Referenced Documents2.1 ASTM Standards:2D 15 Methods of Compound and Sample Preparation forPhysical Testing of Rubber Products3D 412 Tes
6、t Methods for Vulcanized Rubber and Thermo-plastic ElastomersTensionD 1349 Practice for RubberStandard Temperatures forTestingD 3182 Practice for RubberMaterials, Equipment, andProcedures for Mixing Standard Compounds and Prepar-ing Standard Vulcanized SheetsD 3183 Practice for RubberPreparation of
7、Pieces for TestPurposes from ProductsD 3184 Test Methods for RubberEvaluation of NR(Natural Rubber)D 3185 Test Methods for RubberEvaluation of SBR(Styrene-Butadiene Rubber) Including Mixtures With OilD 4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black Man
8、ufacturingIndustriesE 145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Summary of Test Method3.1 Specimens of vulcanized rubber are exposed to thedeteriorating influence of air at specified elevated temperaturesfor known periods of time, after which their physical propertiesar
9、e determined. These are compared with the properties deter-mined on the original specimens and the changes noted.3.2 Unless otherwise specified, the determination of thephysical properties shall be carried out in accordance with TestMethods D 412.3.3 Except as may be otherwise specified in this test
10、method, the requirements of Practices D 3182 and D 3183 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.4. Sig
11、nificance and Use4.1 Rubber and rubber products must resist the deteriorationof physical properties with time caused by oxidative andthermal aging. This test method provides a way to assess theseperformance characteristics of rubber, under certain acceler-ated conditions as specified.4.2 Please refe
12、r to Annex A1 for important information onstandard compounds used for precision testing for acceleratedtest aging evaluation.5. Apparatus5.1 Type IIB ovens specified in Test Method E 145 aresatisfactory for use through 70C. For higher temperatures,Type IIA ovens are necessary.5.1.1 The interior size
13、 shall be as follows or of an equivalentvolume: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 July 1, 2004. Published July 2004. Originally approvedin 1940. Last previous
14、 edition approved in 1999 as D 573 99.2For 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.3Withdrawn.1Copyright A
15、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Interior size of air oven:min 300 by 300 by 300 mm (12 by 12 by 12 in.)max 900 by 900 by 1200 mm (36 by 36 by 48 in.)5.1.2 Provision shall be made for suspending specimensvertically without touchin
16、g each other or the sides of the agingchamber.5.1.3 The heating medium for the aging chamber shall be aircirculated within it at atmospheric pressure.5.1.4 The source of heat is optional but shall be located inthe air supply outside of the aging chamber proper.5.1.5 The temperature should be automat
17、ically recordedover the entire test period using a temperature-measuringdevice capable of measuring at the specified temperature towithin 61C. Located in the upper central portion of thechamber near the center of the aging specimens. For apparatusnot equipped with automatic recording capabilities, t
18、empera-ture shall be measured with sufficient frequency to ascertainthat the temperature limits specified in 10.2 are adhered to.5.1.6 Automatic temperature control by means of thermo-static regulation shall be used.5.1.7 The following special precautions shall be taken inorder that accurate, unifor
19、m heating is obtained in all parts ofthe aging chamber:5.1.7.1 The heated air shall be thoroughly circulated in theoven by means of mechanical agitation. When a motor-drivenfan is used, the air must not come in contact with the fan motorbrush discharge because of danger of ozone formation.5.1.7.2 Ba
20、ffles shall be used as required to prevent localoverheating and dead spots.5.1.7.3 The thermostatic control device shall be so locatedas to give accurate temperature control of the heating medium.The preferred location is adjacent to the recording thermom-eter.5.1.7.4 An actual check shall be made b
21、y means of maxi-mum reading thermometers placed in various parts of the ovento verify the uniformity of the heating.6. Sampling6.1 The sample size shall be sufficient to allow for thedetermination of the original properties on three specimens andalso on three or more specimens for each exposure peri
22、od ofthe test. At least 24 h must elapse between completion of thevulcanization of the samples and the start of the aging test.6.2 When minimum requirements are specified, one test onthree dumbbells shall be considered sufficient. But if the resultsare below the specified requirements, two additiona
23、l specimensshall be prepared from the original sample and tested. Shouldthe results of either of these tests be below the specifiedrequirements, the sample shall be considered to have failed tomeet the specifications.7. Test Specimens7.1 Dumbbell-shaped specimens prepared as described inTest Methods
24、 D 412 shall be considered standard. Their formshall be such that no mechanical, chemical, or heat treatmentwill be required after exposure. If any adjustments (forexample, to thickness) are necessary, they should be performedprior to exposure.7.2 The cross-sectional dimensions of test specimens for
25、calculating the physical properties shall be measured prior toexposure in the aging chamber. Gage lines used for measuringelongation shall be applied after the specimens have been aged.Only specimens of similar dimensions having approximatelythe same exposed areas may be compared with each other.8.
26、Number of Test Specimens8.1 At least three test specimens shall be used to determinethe original physical properties of each sample and also threeor more specimens of the same material for each exposureperiod of the test.8.2 When minimum requirements are specified, one testshall be made for tensile
27、strength and elongation. If the resultsare below the specified requirements, two additional specimensshall be prepared from the original sample and tested. Shouldthe results of either of these tests be below the specifiedrequirements, the samples shall be considered to have failed tomeet the specifi
28、cations.9. Tests of Unaged Specimens9.1 The stress-strain properties or tensile strength and ulti-mate elongation and any other required properties of theoriginal unaged specimens shall be determined within 96 h ofthe start of the aging period. Results on specimens that arefound to be imperfect shal
29、l be discarded and retests shall bemade.9.2 When rubber compounds are to be tested for the purposeof determining compliance with specifications, it shall bepermissible to determine the original properties required in 9.1simultaneously with the determination of the values after thefirst aging period
30、even though the elapsed time exceeds 96 h.10. Procedure for Accelerated Aging10.1 Place the specimens for aging in the oven after it hasbeen preheated to the operating temperature. If possible, avoidsimultaneous aging of a mixed group of different compounds.For instance, high-sulfur compounds should
31、 not be aged withlow-sulfur compounds and those containing antioxidants shallnot be aged with those having no antioxidants. Some migrationis known to occur.10.2 The operating temperature may be any elevated stan-dard temperature as shown in Practice D 1349, as agreed upon.NOTE 1Caution: It should be
32、 noted that, for each 10C increase intemperature, the rate of oxidation may be approximately double. Withrapid aging types of rubber or those containing or contaminated by certainoxidizing chemicals, the rate of oxidation may be catalyzed to such anextent as to become violent with increasing tempera
33、tures.10.3 Start the aging interval at the time the specimens areplaced in the oven and continue for a measured time interval.The selection of suitable intervals of aging will depend on therate of deterioration of the particular material being tested.Intervals frequently used are 3, 7, and 14 days.1
34、0.4 Use aging intervals such that the deterioration will notbe so great as to prevent determination of the final physicalproperties. In experimental work, it is desirable to use a rangeof periods, while for routine tests of known materials, fewerintervals may be employed.D57304210.5 At the terminati
35、on of the aging interval, remove thespecimens from the oven, cool to room temperature on a flatsurface, and allow them to rest not less than 16 h nor more than96 h before determination of the physical properties. Apply thegage lines to the specimens for use in measuring elongations.11. Physical Test
36、s of Aged Specimens11.1 The tensile strength and ultimate elongation or thestress-strain properties of the specimens aged for differentintervals shall be determined as the intervals terminate in theprogress of aging, disregarding the fact that more specimensmay still be aging. In determining the phy
37、sical properties afteraging, the final values shall be the median of results from threespecimens except that under the following conditions twoadditional specimens shall be exposed and tested and themedian of the values for the five specimens shall be used:11.1.1 If one or more values do not meet th
38、e specifiedrequirements when testing for compliance with specifications.11.1.2 If referee tests are being made. After completion ofthe tests, the broken specimens shall be examined visually andmanually and their condition noted.12. Calculation12.1 Express the results of the aging test as a percentag
39、e ofthe change in each physical property (tensile strength, ultimateelongation, or tensile stress), calculated as follows:P 5 A 2 O!/O 3 100 (1)where:P = percentage change in property,O = original value, andA = value after aging.13. Report13.1 Report the following information:13.1.1 The results calc
40、ulated in accordance with Section 12,13.1.2 All observed and recorded data on which the calcu-lations are based,13.1.3 Type of aging test,13.1.4 Aging interval,13.1.5 Aging temperature,13.1.6 Duration, temperature, and data of vulcanization ofthe rubber, if known,13.1.7 Dates of original and final d
41、eterminations of physicalproperties, and13.1.8 Dimensions of test specimens.14. Precision and Bias414.1 This precision and bias section has been prepared inaccordance with Practice D 4483. Refer to this practice forterminology and other statistical calculation details.14.2 A Type 2 (interlaboratory)
42、 precision was evaluated in1974. Both repeatability and reproducibility are short term, aperiod of a few days separates replicate test results. A test resultis expressed on the basis of a median value, as specified by TestMethods D 412 obtained on three determinations or measure-ments of the propert
43、y or parameter in question.14.3 Six different materials were used in the interlaboratoryprogram, these were tested in three laboratories on twodifferent days. These precision results were obtained for avariety of compounds prepared in accordance with MethodsD 15 prior to its removal from the Annual
44、Book of ASTMStandards. Please see Annex A1 for more details on this work.14.4 The results of the precision calculations for repeatabil-ity and reproducibility for both percent tensile strength changeand percent elongation change are given in Table 1, inascending order of material average or level, f
45、or each of thematerials evaluated.14.4.1 The precision of this test method may be expressed inthe format of the following statements that use an appropriatevalue of r, R, (r),or(R), that is, that value to be used indecisions about test results (obtained with the test method).The appropriate value is
46、 that value of r or R associated with amean level in the precision tables closest to the mean levelunder consideration at any given time, for any given material inroutine testing operation.14.5 Repeatability The repeatability, r, of this test methodhas been established as the appropriate value tabul
47、ated in theprecision tables. Two single test results, obtained under normaltest method procedures, that differ by more than this tabulatedr (for any given level) must be considered as derived fromdifferent or non-identical sample populations.14.6 Reproducibility The reproducibility, R, of this testm
48、ethod has been established as the appropriate value tabulated4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D11-1056.TABLE 1 Type 2 Precision Results100C AgingPart 1Percent Tensile Strength Change, 48 hMaterial orCompoundMean
49、TestLevelWithinLaboratoriesBetweenLaboratoriesSr r SR RNR (1G) 56.6 3.28 9.28 5.91 16.7SBR (9B) 14.2 3.42 9.68 3.02 8.55NBR (1F) 11.5 2.46 6.96 2.49 7.05CR (2D) 10.6 3.83 10.8 5.11 14.5OESBR (10B3) 7.6 2.34 6.62 5.56 15.7IIR (2E) 1.1 3.47 9.82 3.77 10.7Pooled Values . 3.18 9.00 3.90 11.04Part 2Percent Change in Elongation, Average of 48, 96 h AgingNR (1G) 55.6 5.08 14.4 7.79 22.0SBR (9B) 48.3 5.38 15.2 6.09 17.2OESBR (10B3) 40.5 3.20 9.06 5.11 14.5NBR (1F) 39.6 7.10 20.1 7.11 20.1CR (2D) 12.1 7.85 22.2 9.00 25.5IIR (2E) 6.2 2.56 7.24 3.97 11.2Pooled Val
