1、Designation: D2137 11Standard 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 May 1, 2011. Published July 2011. Originally approvedin 1962. Last previous edition approved in 2010 as D2137 10
15、. DOI: 10.1520/D2137-11.2For 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, 100 Ba
16、rr 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 Positio
17、n 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 Test
18、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 dim
19、ensional 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 med
20、ium, 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 media
21、, 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 been
22、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 of li
23、quid 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 th
24、e 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 providedfor c
25、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, digital or analog, having a r
26、esolution 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 located
27、 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 a s
28、ystem 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, control
29、s 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 temperature
30、, 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 atinterva
31、ls 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-canizat
32、ion 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 sho
33、uld 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 results.
34、Their use shall be indicated in the test report.FIG. 1 Specimen Clamp and StrikerD2137 1127.1.2 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 the te
35、st 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 2.0
36、 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 to m
37、aintain 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 disfiguremen
38、tshall 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 les
39、sthan 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 may
40、 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 bring
41、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. Immerse th
42、especimens for 5.0 6 0.5 min at the test temperature. Theimmersion time shall be reported in 10.1.2.(1) Alternatively, an immersion time of 3.0 6 0.5 min maybe employed. The immersion time shall be reported in 10.1.2.9.1.1.3 If five specimens as illustrated in Fig. 3 are used, aminimum of 6 mm (0.25
43、 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 same 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 b
44、elow 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 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 tempe
45、rature 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, fissure, or holevisible to the naked eye, or complete separation into two ormore pieces. When a specimen has not completely separated,bend it to
46、 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 temperatures at10C intervals using new specimens each time until no failureis obtained. Then decrease the bath temperature at 2C inter-vals. Test a
47、t 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 with Gaseous Heat Transfer Medium:(1) Adjust the refrigerating unit and bring the test chamber,test apparatus, and specimens to thermal equ
48、ilibrium 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 air.(2) The actual testing is performed in the same manner asdescribed in
49、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. The 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.NOTEThe test piece thickness is 2.0 6 0.2 mm.FIG. 2 Test Method A (Modified T-50) Test Specimen (formerlyreferred to as Type B Specimen)FIG. 3 Test Meth
