1、Designation: D 2137 05Standard Test Methods forRubber PropertyBrittleness Point of Flexible Polymersand Coated Fabrics1This standard is issued under the fixed designation D 2137; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses 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 These test methods cover the
3、 determination of thelowest temperature at which rubber vulcanizates and rubber-coated fabrics will not exhibit fractures or coating cracks whensubjected to specified impact conditions.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for inform
4、ationonly.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 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Re
5、ferenced Documents2.1 ASTM Standards:2D 751 Test Methods for Coated FabricsD 832 Practice for Rubber Conditioning for Low-Temperature TestingD 4483 Practice for Determining Precision for Test MethodStandards in the Rubber and Carbon Black Industries3. Summary of Test Methods3.1 A specified number of
6、 specimens is given a single-impact under specified impact and temperature conditions untilthe temperature is found at which no failures occur. This isdefined as the brittleness temperature.3.2 There are two test methods:3.2.1 Test Method ACovers the determination of thelowest temperature at which r
7、ubber vulcanizates will notfracture or crack.3.2.2 Test Method BCovers the determination of thelowest temperature at which rubber-coated fabrics will notfracture or exhibit coating cracks.3.3 The test can be done either in a liquid heat transfermedia or in a gaseous media.4. Significance and Use4.1
8、These test methods cover the evaluation of rubbermaterials or fabrics coated therewith subjected to low-temperature flex with an impact under well-defined conditionsof striker speed. The response is largely dependent on effects oflow temperatures such as crystallization, incompatibility ofplasticize
9、r, or the inherent dynamic behavior of the materialitself. Data obtained by these test methods may be used topredict the product behavior in applications where the condi-tions are similar to those specified in these test methods.4.2 These test methods have been found useful for specifi-cation and de
10、velopment purposes but do not necessarilyindicate the lowest temperature at which the material may beused.5. Apparatus5.1 Specimen Clamp, designed so as to hold firmly thespecimen(s) as cantilever beams (Fig. 1).5.2 StrikerThe edge of the striker shall have a radius of1.6 6 0.1 mm (0.063 6 0.005 in.
11、). The edge shall moverelative to the specimen at a rectilinear speed of 2.0 6 0.2 m/s(6.6 6 0.6 ft/s) at impact and immediately after. The speed ofthe solenoid-activated striker should be frequently calibratedby the method described in the annex. Other types of testersshall be calibrated according
12、to their appropriate methods. Inorder to have the required speed, care must be taken to ensurethat the striking energy of at least 3.0 J per specimen is used.NOTE 1The striker may be motor-driven, solenoid-operated, gravity-activated or spring-loaded. The motor-driven tester should be equippedwith a
13、 safety interlock to prevent striker motion when the cover is open.1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.14 on Time andTemperature-Dependent Physical Properties.Current edition approved Oct. 1, 2005. Publis
14、hed October 2005. Originallyapproved in 1962. Last previous edition approved in 2000 as D 213794(2000).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
15、 Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2.1 Position of Striking EdgeThe distance between thecenter line of the striking edge and the clamps shall be 8.0 60.3 mm (0.31 6 0.01 in.).
16、The clearance between the strikingarm and the clamp at and immediately following impact shallbe:5.2.1.1 Test Method A 6.4 6 0.3 mm (0.25 6 0.01 in.)5.2.1.2 Test Method B Listed as follows:Specimen Thickness, mm (in.) Clearance, mm (in.)1.65 to 2.20 (0.065 to 0.087) 6.4 6 0.3 (0.25 6 0.01)1.05 to 1.6
17、4 (0.041 to 0.064) 5.7 6 0.3 (0.22 6 0.01)0.55 to 1.04 (0.022 to 0.040) 5.2 6 0.3 (0.20 6 0.01)0.10 to 0.54 (0.004 to 0.021) 4.8 6 0.3 (0.19 6 0.01)NOTE 2The dimensional requirements for Test Method B may beobtained by fabricating individual plates to fit the specimen holderillustrated in Fig. 1.5.3
18、 Tank or Test ChamberA tank for liquid heat transfermedia or a test chamber for gaseous media is required. Toensure thorough circulation of the heat transfer medium, astirrer should be provided for liquids and a fan or blower forgaseous media.5.4 Heat Transfer Media:5.4.1 Liquid Heat Transfer Medium
19、Methanol is the rec-ommended heat transfer medium. Since methanol is flammableand toxic, the bath should be isolated in a closed hood.NOTE 3Any other liquid heat transfer medium that remains fluid atthe test temperature and will not appreciably affect the material tested maybe used. The following ma
20、terials have been used down to the indicatedtemperatures.Dow Corning200 fluids: C5mm2/s viscosity 602mm2/s viscosity 76Methanol 90Propyl Alcohol 120NOTE 4The desired temperature may also be obtained by filling thetank with the heat transfer medium and lowering its temperature by theaddition of liqui
21、d carbon dioxide controlled by a solenoid-activated unitwith an associated temperature control. Where temperatures below thatobtainable by solid or liquid carbon dioxide are required, liquid nitrogenmay be used.5.4.2 Gaseous Medium A gaseous medium may be usedprovided ample time is allowed for the s
22、pecimens to reachtemperature equilibrium with the temperature of the medium.NOTE 5The apparatus may be used in a gaseous medium if it can beshown that low temperature will not affect the operation of the solenoid-activated impact mechanism.5.5 Temperature ControlSuitable means shall be providedfor c
23、ontrolling the temperature of the heat transfer mediumwithin 60.5C (61F) if the medium is liquid and within61C (61.8F) with gaseous medium.5.5.1 Temperature monitoring is done with a thermocoupleor other temperature-sensing device with associated tempera-ture indicator graduated in 0.5C (1F) divisio
24、ns and having arange suitable for the temperatures at which the tests are to bemade. The thermocouple is preferably constructed of copper-constantan wire having a diameter between 0.2 and 0.5 mm (32to 24 Awg) and shall be fusion-bonded at the junction. It shallbe located as near the specimens as pos
25、sible. A thermometermay also be used if it can be shown to agree with thethermocouple and other devices that respond rapidly to tem-perature change.5.5.2 Automatic changes in temperature of a liquid mediummay be obtained by means of a system consisting of anexternally cooled tank connected to the te
26、st area with suitabletubing, a thermoregulator, a pump, an electric immersionheater, and mercury switches. The regulator, alternately acti-vating both the pump and heater through the mercury switches,controls the amount of liquid coolant being pumped to the testarea as well as the amount of heat com
27、ing from the heater.5.5.3 Manual temperature changes for liquid media may beaccomplished with powdered carbon dioxide (dry ice) and anelectric immersion heater.6. Time Lapse Between Vulcanization and Testing6.1 For all test purposes, the minimum time between vul-canization and testing shall be 16 h.
28、6.2 For nonproduct tests, the maximum time between vul-canization and testing should be four weeks, and for evaluationintended to be comparable, the tests should be carried out afterthe same time interval.6.3 For product tests, whenever possible, the time betweenvulcanization and testing should not
29、exceed three months. Inother cases, tests should be made within two months of the dateof receipt by the customer.7. Test Specimens7.1 Test Method AThe die-punched Type B specimens asillustrated in Fig. 2 shall be used.NOTE 6Type A strips 40 6 6 mm (1.6 6 0.25 in.) long, 6 6 0.5 mm(0.25 6 0.02 in.) w
30、ide, and 2.0 6 0.2 mm (0.08 6 0.01 in.) thick (see Fig.3) may be used but will not necessarily give comparable results.NOTE 7Specimens of other than 2.0 6 0.2 mm (0.08 6 0.01 in.)thicknesses may be used provided it can be shown that they giveequivalent results for the material being tested.7.2 Test
31、Method BType A specimens shall be used. Theyshould be die-punched with the longer dimensions parallel tothe lengthwise direction of the coated fabric, unless otherwisespecified, and be 40 6 6 mm (1.6 6 0.25 in.) long and 6 6 0.5mm (0.25 6 0.02 in.) wide.FIG. 1 Specimen Clamp and StrikerNOTEThe test
32、piece thickness is 2.0 6 0.2 mm.FIG. 2 Modified T-50 Test PieceD2137052NOTE 8Sharp dies must be used in the preparation of specimens ifreliable results are to be achieved. Careful maintenance of die cuttingedges is extremely important and can be obtained by frequent light honingtouching up with jewe
33、lers honing stones.8. Conditioning8.1 Test Method ACondition the test specimens at 23 62C (73.4 6 3.6F) and 50 6 5 % relative humidity for no lessthan 16 h prior to testing.8.2 Test Method BThe test specimens shall be conditionedprior to the test in accordance with the standard conditions inTest Met
34、hods D 751.8.3 Where long-term effects, such as crystallization, incom-patibility, etc., of the material, are to be studied, the testspecimens may be conditioned in accordance with PracticeD 832.9. Procedure9.1 Test Method A:9.1.1 Test with Liquid Heat Transfer Medium:9.1.1.1 Prepare and bring the b
35、ath to a temperature belowthe expected lowest temperature of non-failure. Place sufficientliquid in the tank to ensure approximately 25 mm (1 in.) liquidcovering the test specimens.9.1.1.2 Mount five Type B specimens in the apparatus withthe entire tab in the clamp. Immerse the specimens for 3.0 60.
36、5 min at the test temperature.NOTE 9If five Type A specimens are used, a minimum of 6 mm(0.25 in.) of the specimen length must be held in the clamp.NOTE 10If the energy capacity of the apparatus causes the speed ofthe striker to fall below 1.8 m/s (6 ft/s), a smaller number of specimensmay be mounte
37、d.9.1.1.3 After immersion for the specified time, record theactual test temperature and deliver a single impact to thespecimens.9.1.1.4 Examine each specimen to determine whether or notit has failed. Failure is defined as any crack, fissure, or holevisible to the naked eye, or complete separation in
38、to two ormore pieces. When a specimen has not completely separated,bend it to an angle of 90 in the same direction as the bendcaused by the impact, then examine it for cracks at the bend.9.1.1.5 Repeat the test at the next higher temperatures at10C intervals using new specimens each time until no fa
39、ilureis obtained. Then decrease the bath temperature at 2 intervals.Test at each temperature to determine the lowest temperature atwhich no failures occur. Record this temperature as the lowesttemperature of non-failure.9.2 Test with Gaseous Heat Transfer Medium:9.2.1 Adjust the refrigerating unit a
40、nd bring the test cham-ber, test apparatus, and specimens to thermal equilibrium at thedesired temperature (see Note 4). An alternative method is toplace the striker and specimen clamp through the top of therefrigerating unit with the solenoid remaining outside the unitand insulated from the cold ai
41、r.9.2.2 The actual testing is performed in the same manner asdescribed in 9.1.1.9.3 Testing of Materials from Approved Supplier:9.3.1 For inspection and acceptance of materials receivedfrom an approved supplier, it shall be satisfactory to accept lotson the basis of testing ten specimens (five at a
42、time) at aspecified temperature as stated in the relevant material speci-fications. Not more than five shall fail. Should there be nofailures in the testing of the first five specimens, the testing ofthe second five specimens is not required.9.3.2 It shall be satisfactory to accept rubber compositio
43、nson a basis of testing five specimens at a specified temperature,as stated in the relevant material specification. None shall fail.9.4 Test Method B:9.4.1 Follow the instructions in accordance with 9.1.1.1through 9.1.1.3, except that Type A specimens shall be used.The specimens shall be examined fo
44、r any visible fracture orcrack in the coating under a 53 magnifier, after having bent thespecimens to an angle of 180 in the same direction caused bythe impact.9.4.2 Use new specimens for each test.9.4.3 For routine testing of all coated fabrics, subject fivespecimens to the impact test at a specifi
45、ed temperature as statedin the relevant material specification. None shall fail.10. Report10.1 Report the following information:10.1.1 Complete identification of the material tested, includ-ing type, source, manufacturers code designation, form, anddate produced, if applicable,10.1.2 Thickness and t
46、ype of specimen,10.1.3 Number of specimens tested at a single impact ifother than five,10.1.4 Conditioning period, method, and procedure,10.1.5 Test method used,10.1.6 Heat transfer medium used, and10.1.7 Brittleness temperature to nearest 1C (2F).11. Precision and Bias311.1 This precision and bias
47、section has been prepared inaccordance with Practice D 4483. Refer to Practice D 4483 forterminology and other statistical calculation details.11.2 A Type 1 (interlaboratory) precision was evaluated in1987. Both repeatability and reproducibility are short term. Aperiod of a few days separates replic
48、ate test results. A testresult, as specified by this test method, is obtained on onedetermination or measurement of the property or parameter inquestion.11.3 Four different materials were used in the interlabora-tory program. These were tested in seven laboratories on twodifferent days.11.4 The resu
49、lts of the precision calculations for repeatabil-ity and reproducibility are given in Table 1, in ascending order3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D11-1052.FIG.3aTypeASpecimenD2137053of material average or level, for each of the materials evalu-ated. Measurements, in C, have been transformed to kelvin asthe brittleness temperature of one of the materials is approxi-mately 0C.11.5 Repeatability, r, does not vary over the range ofmaterial levels as eval
