1、Designation: D573 04 (Reapproved 2015)Standard Test Method forRubberDeterioration in an Air Oven1This standard is issued under the fixed designation D573; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 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
3、 theinfluence of elevated 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 laborator
4、y com-parison basis.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 stand
5、ard to establish appro-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:2D15 Method of Compound and Sample Preparation forPhysical Testing of Rubber
6、Products (Withdrawn 1975)3D412 Test Methods for Vulcanized Rubber and Thermoplas-tic ElastomersTensionD1349 Practice for RubberStandard Conditions for Test-ingD3182 Practice for RubberMaterials, Equipment, and Pro-cedures for Mixing Standard Compounds and PreparingStandard Vulcanized SheetsD3183 Pra
7、ctice for RubberPreparation of Pieces for TestPurposes from ProductsD3184 Practice for RubberEvaluation of NR (NaturalRubber)D3185 Test Methods for RubberEvaluation of SBR(Styrene-Butadiene Rubber) Including Mixtures With OilD4483 Practice for Evaluating Precision for Test MethodStandards in the Rub
8、ber and Carbon Black ManufacturingIndustriesE145 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 thei
9、r physical propertiesare 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 D412.3.3 Except as may be otherwise
10、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 ta
11、ke precedence.4. Significance 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 speci
12、fied.4.2 Please refer 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 E145 aresatisfactory for use through 70C. For higher temperatures,Type IIA ovens are necessary.5.1.
13、1 The interior size 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, 2015. Published October 2015. Originallyapproved
14、in 1940. Last previous edition approved in 2010 as D573 04 (2010).DOI: 10.1520/D0573-04R15.2For 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 Su
15、mmary 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 States1Interior size of air oven:min 300 by 300 by 300 mm (12 by 12 by 12 in.)m
16、ax 900 by 900 by 1200 mm (36 by 36 by 48 in.)5.1.2 Provision shall be made for suspending specimensvertically without touching 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
17、is optional but shall be located inthe air supply outside of the aging chamber proper.5.1.5 The temperature should be automatically recordedover the entire test period using a temperature-measuringdevice capable of measuring at the specified temperature towithin 61C. Located in the upper central por
18、tion of thechamber near the center of the aging specimens. For apparatusnot equipped with automatic recording capabilities, tempera-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 o
19、f thermo-static regulation shall be used.5.1.7 The following special precautions shall be taken inorder that accurate, uniform 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-drivenfa
20、n is used, the air must not come in contact with the fan motorbrush discharge because of danger of ozone formation.5.1.7.2 Baffles 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 o
21、f the heating medium.The preferred location is adjacent to the recording thermom-eter.5.1.7.4 An actual check shall be made by 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
22、 for thedetermination of the original properties on three specimens andalso on three or more specimens for each exposure period 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
23、 test onthree dumbbells shall be considered sufficient. But 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 sample shall be considered
24、 to have failed tomeet the specifications.7. Test Specimens7.1 Dumbbell-shaped specimens prepared as described inTest Methods D412 shall be considered standard. Their formshall be such that no mechanical, chemical, or heat treatmentwill be required after exposure. If any adjustments (forexample, to
25、thickness) are necessary, they should be performedprior to exposure.7.2 The cross-sectional dimensions of test specimens forcalculating the physical properties shall be measured prior toexposure in the aging chamber. Gage lines used for measuringelongation shall be applied after the specimens have b
26、een aged.Only specimens of similar dimensions having approximatelythe same exposed areas may be compared with each other.8. 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
27、material for each exposureperiod of the test.8.2 When minimum requirements are specified, one testshall be made for tensile strength and elongation. If the resultsare below the specified requirements, two additional specimensshall be prepared from the original sample and tested. Shouldthe results of
28、 either of these tests be below the specifiedrequirements, the samples shall be considered to have failed tomeet the specifications.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 specim
29、ens shall be determined within 96 h ofthe start of the aging period. Results on specimens that arefound to be imperfect shall 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 deter
30、mine the original properties required in 9.1simultaneously with the determination of the values after thefirst aging period 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 temperat
31、ure. If possible, avoidsimultaneous aging of a mixed group of different compounds.For instance, high-sulfur compounds should 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 t
32、emperature may be any elevated stan-dard temperature as shown in Practice D1349, as agreed upon.NOTE 1Caution: It should be 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 certa
33、inoxidizing chemicals, the rate of oxidation may be catalyzed to such anextent as to become violent with increasing temperatures.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 d
34、epend on therate of deterioration of the particular material being tested.Intervals frequently used are 3, 7, and 14 days.10.4 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
35、 a rangeD573 04 (2015)2of periods, while for routine tests of known materials, fewerintervals may be employed.10.5 At the termination 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 befor
36、e determination of the physical properties. Apply thegage lines to the specimens for use in measuring elongations.11. Physical Tests of Aged Specimens11.1 The tensile strength and ultimate elongation or thestress-strain properties of the specimens aged for differentintervals shall be determined as t
37、he intervals terminate in theprogress of aging, disregarding the fact that more specimensmay still be aging. In determining the physical properties afteraging, the final values shall be the median of results from threespecimens except that under the following conditions twoadditional specimens shall
38、 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 the specifiedrequirements when testing for compliance with specifications.11.1.2 If referee tests are being made. After completion ofthe tests, the broken specimens shall
39、be examined visually andmanually and their condition noted.12. Calculation12.1 Express the results of the aging test as a percentage ofthe change in each physical property (tensile strength, ultimateelongation, or tensile stress), calculated as follows:P 5 A 2 O!/O# 3100 (1)where:P = percentage chan
40、ge in property,O = original value, andA = value after aging.13. Report13.1 Report the following information:13.1.1 The results calculated 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 Ag
41、ing temperature,13.1.6 Duration, temperature, and data of vulcanization ofthe rubber, if known,13.1.7 Dates of original and final determinations of physicalproperties, and13.1.8 Dimensions of test specimens.14. Precision and Bias414.1 This precision and bias section has been prepared inaccordance wi
42、th Practice D4483. Refer to this practice forterminology and other statistical calculation details.14.2 A Type 2 (interlaboratory) precision was evaluated in1974. Both repeatability and reproducibility are short term, aperiod of a few days separates replicate test results.Atest resultis expressed on
43、 the basis of a median value, as specified by TestMethods D412 obtained on three determinations or measure-ments of the property or parameter in question.14.3 Six different materials were used in the interlaboratoryprogram, these were tested in three laboratories on twodifferent days. These precisio
44、n results were obtained for avariety of compounds prepared in accordance with MethodsD15 prior to its removal from the Annual 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 percen
45、t tensile strength changeand percent elongation change are given in Table 1,inascending order of material average or level, for 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),
46、or(R), that is, that value to be used indecisions about test results (obtained with the test method).The appropriate value is 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 test
47、ing operation.14.5 RepeatabilityThe repeatability, r, of this test methodhas been established as the appropriate value tabulated in theprecision tables. Two single test results, obtained under normaltest method procedures, that differ by more than this tabulated4Supporting data have been filed at AS
48、TM 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 TestLevelWithinLaboratoriesBetweenLaboratoriesSr r SR RNR (1G) 56.6 3.28 9.28 5.91 16.7SBR (9B) 14.2
49、 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 Values . 5.20 14.7 6.51 18.4NOTE 1The averaging of results for 48 and 96 h of aging gives anincreased
