1、Designation: D2137 10Standard Test Methods forRubber PropertyBrittleness Point of Flexible Polymersand Coated Fabrics1This standard is issued under the fixed designation D2137; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 Department of Defense.1. Scope1.1 These test methods cover the de
3、termination 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 asstandard. The values given in parentheses are for informationon
4、ly.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. Reference
5、d Documents2.1 ASTM Standards:2D751 Test Methods for Coated FabricsD832 Practice for Rubber Conditioning For Low Tempera-ture TestingD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3. Summary of Test Methods3.1 A specified number
6、 of 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 four test methods:3.2.1 Test Method AThe determination of the lowesttemperature at which rubb
7、er vulcanizates will not fracture orcrack (refer to 9.1).3.2.2 Test Method BThe determination of the lowesttemperature at which rubber-coated fabrics will not fracture orexhibit coating cracks (refer to 9.2).3.2.3 Test Method CTesting at a specified temperature andtesting of materials from a supplie
8、r (refer to 9.3). This methodis used for the classification of materials and for specificationpurposes.3.2.4 Test Method DThe determination of 50 % brittle-ness temperature (refer to 9.4). This is the temperature at which50 % of the specimens fail.3.3 These tests may be performed either in a liquid
9、heattransfer media or in a gaseous media (refer to 9.1.1.9).4. Significance and Use4.1 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 depend
10、ent on effects oflow temperatures such as crystallization, incompatibility ofplasticizer, 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 the
11、se test methods.4.2 These test methods have been found useful for specifi-cation and development 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
12、.2 StrikerThe edge of the striker shall have a radius of1.6 6 0.1 mm (0.063 6 0.005 in.). 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
13、the method described in the annex. Other types of testersshall be calibrated according to their appropriate methods andmanufacturers instructions. In order to have the requiredspeed, care must be taken to ensure that the striking energy ofat least 3.0 J per specimen is used.1These test methods are u
14、nder 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, 2010. Published November 2010. Originallyapproved in 1962. Last previous edition approved in 2005 as D21
15、37 05. DOI:10.1520/D2137-10.2For 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.1Copyright ASTM International, 10
16、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 1The striker may be motor-driven, solenoid-operated, gravity-activated or spring-loaded. The motor-driven tester should be equippedwith a safety interlock to prevent striker motion when the cover is open.5.2.1 Pos
17、ition 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.). The clearance between the strikingarm and the clamp at and immediately following impact shallbe:5.2.1.1 Test Method A, C, and D 6.4 6 0.3 mm (0.25 60.01 in.)5.2.1.2 T
18、est 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 1.64 (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
19、 dimensional requirements for Test Method B may beobtained by fabricating individual plates to fit the specimen holderillustrated in Fig. 1.5.3 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
20、 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 MediumThe recommendedheat transfer media are listed below. Methanol is typicallyused, however, it is both flammable and toxic. Methanol, orany flammable or toxic m
21、edia, shall be used only in a tank/testchamber which is specifically designed and manufactured toaccommodate such media.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 materials have b
22、een used down to the indicatedtemperatures.Dow Corning200 fluids: C5mm2/s viscosity 602mm2/s viscosity 76Methanol 90Propyl Alcohol or methylcyclohexane 120NOTE 4The desired temperature may also be obtained by filling thetank with the heat transfer medium and lowering its temperature by theaddition o
23、f liquid 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 fo
24、r the specimens to reachtemperature equilibrium with the temperature of the medium.5.4.2.1 A gaseous medium may be used if the low tempera-ture will not affect the operation of the impact mechanism andremains fluid at the specified temperature.5.5 Temperature ControlSuitable means shall be providedf
25、or controlling 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, digital or analog, having
26、 a resolution of 0.5C(1F) or greater and a range suitable for the temperatures atwhich the tests are to be made.5.5.2 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 loc
27、ated as near the specimens as possible without makingcontact. A thermometer may also be used if it can be shown toagree with the thermocouple or other devices that respondrapidly and accurately to temperature change.5.5.3 Automatic changes in temperature of a liquid mediummay be obtained by means of
28、 a system consisting of anexternally cooled tank connected to the test area with suitabletubing, a thermoregulator, a pump, an electric immersionheater or internal heat exchanger, and appropriate switches.The regulator, alternately activating both the pump and heatingsystem through the switches, con
29、trols the amount of liquidcoolant being pumped to the test chamber as well as theamount of heat coming from the heater.5.5.4 Manual temperature changes for liquid media may beaccomplished with powdered carbon dioxide (dry ice) and anelectric immersion heater.5.5.5 Devices employed to monitor tempera
30、ture, thermo-couples or liquid-in-glass thermometers, shall be calibrated atintervals recommended by the manufacturer. If no interval isrecommended a one year interval is suggested.5.5.6 Devices employed to control temperature, typicallythermocouples and associated devices, shall be calibrated atint
31、ervals recommended by the manufacturer. If no interval isrecommended a one year interval is suggested.6. Time Lapse Between Vulcanization and Testing6.1 For all test purposes, the minimum time between vul-canization and testing shall be 16 h.6.2 For nonproduct tests, the maximum time between vul-can
32、ization and testing should be 672 h (four weeks), and forevaluation intended to be comparable, the tests should becarried out after the same time interval.6.3 For product tests, whenever possible, the time betweenvulcanization and testing should not exceed 2160 h (threemonths). In other cases, tests
33、 should be made within 1440 h(two months) of the date of receipt by the customer.7. Test Specimens7.1 Test Method ADie-cut specimens as illustrated in Fig.2 shall be considered standard.7.1.1 Test Method B specimens as illustrated in Fig. 3 maybe used but will not necessarily provide comparable resu
34、lts.Their use shall be indicated in the test report.FIG. 1 Specimen Clamp and StrikerD2137 1027.1.2 Specimens of other than 2.0 6 0.2 mm (0.08 6 0.01in.) thicknesses may be used provided it can be shown that theygive equivalent results for the material being tested. Their useshall be indicated in th
35、e test report.7.2 Test Method BDie-cut specimens as illustrated in Fig.3 shall be used. They should be die-cut with the longerdimensions parallel to the lengthwise direction of the coatedfabric, unless otherwise specified, and be 40 6 6 mm (1.6 60.25 in.) long, 6 6 0.5 mm (0.25 6 0.02 in.) wide, and
36、 2.0 60.2 mm (0.08 6 0.01 in.) in thickness.7.3 Test Method CDie-cut specimens as illustrated in Fig.1 or Fig. 2 may be used and reported accordingly.7.4 Test Method DDie-cut specimens as illustrated in Fig.1 or Fig. 2 may be used and reported accordingly.7.5 Regular calibration of the cutting dies
37、to maintain theproper geometric dimensions and cutting edge sharpness isimportant in achieving repeatable and reproducible test out-comes. The cutting die knife edges should be regularlyinspected for damage or wear under 103 or greater magnifi-cation. Any cutting die which exhibits nicks or disfigur
38、ementshall be removed from service. It is recommended that cuttingdies be calibrated and sharpened once yearly or more fre-quently depending on the frequency and severity of use.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
39、 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 Methods D751.8.3 Where long-term effects, such as crystallization, incom-patibility, etc., of the material, are to be studied, the testspecimens
40、 may be conditioned in accordance with PracticeD832.8.4 Test Method CCondition the specimens as describedin Test Method A (8.1).8.5 Test Method DCondition the specimens as describedin Test Method A (8.1).9. Procedure9.1 Test Method A:9.1.1 Test with Liquid Heat Transfer Medium:9.1.1.1 Prepare and br
41、ing the bath 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 specimens as illustrated in Fig. 2 in theapparatus with the entire tab in the clamp. Immers
42、e thespecimens for 5.0 6 0.5 min at the test temperature.9.1.1.3 If five specimens as illustrated in Fig. 3 are used, aminimum of 6 mm (0.25 in.) of the specimen length must beheld in the clamp.9.1.1.4 The clamp shall be properly tightened so that eachtest specimen is held with approximately the sam
43、e clampingtorque. A clamping torque of 0.15 to 0.25 N is recommended.9.1.1.5 If the energy capacity causes the speed of the strikerto fall below 1.8 m/s (6 ft/s), a smaller number of specimensshall be mounted for testing so that the striker speed does notfall below 1.8 m/s (6 ft/s). This speed shall
44、 be maintained forat least 6.0 mm of travel following the impact.9.1.1.6 After immersion for the specified time, record theactual test temperature and deliver a single impact to thespecimens.9.1.1.7 Examine each specimen to determine whether or notit has failed. Failure is defined as any crack, fiss
45、ure, or holevisible to the naked eye, or complete separation into 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.9.1.1.8 Repeat the test at the next higher tempera
46、tures at10C intervals using new specimens each time until no failureis obtained. Then decrease the bath temperature at 2C inter-vals. Test at each temperature to determine the lowest tempera-ture at which no failures occur. Record this temperature as thelowest temperature of non-failure.9.1.1.9 Test
47、 with Gaseous Heat Transfer Medium:(1) Adjust the refrigerating unit and bring the test chamber,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 t
48、he solenoid remaining outside the unitand insulated from the cold air.(2) The actual testing is performed in the same manner asdescribed in 9.1.1.9.2 Test Method B:9.2.1 Follow the instructions in accordance with 9.1.1.1through 9.1.1.9, except that specimens as illustrated in Fig. 3shall be used. Th
49、e specimens shall be examined for any visiblefracture or crack in the coating under 53 magnification, afterhaving bent the specimens to an angle of 180 in the samedirection caused by the impact.9.2.2 Use new specimens for each test.9.2.3 For routine testing of all coated fabrics, subject fivespecimens to the impact test at a specified temperature as statedin the relevant material specification. None shall fail.9.3 Test Method CTesting at a Specified Temperature andTesting of Materials from a Supplier:NOTEThe test piece thickness is 2.0 6
