1、Designation: D1053 92a (Reapproved 2018)Standard Test Methods forRubber PropertyStiffening at Low Temperatures: FlexiblePolymers and Coated Fabrics1This standard is issued under the fixed designation D1053; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n the case of revision, the year 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 U.S. Department of Defense.1. Scope
3、1.1 These test methods describe the use of a torsionalapparatus for measuring the relative low temperature stiffeningof flexible polymeric materials and fabrics coated therewith. Aroutine inspection and acceptance procedure, to be used as apass-fail test at a specified temperature, is also described
4、.1.2 These test methods yield comparative data to assess thelow temperature performance of flexible polymers and fabricscoated therewith.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to addr
5、ess all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was devel
6、oped in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Docu
7、ments2.1 ASTM Standards:2D832 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 Method3.1 Test Method A describes the measurement, at lowtemperatures,
8、of the stiffening of flexible polymers.3.2 Test Method B describes the measurement, at lowtemperatures, of the stiffening of fabrics coated with flexiblepolymers.3.3 In these test methods, a specimen of flexible polymer orfabric coated with flexible polymer is secured and connected inseries to a wir
9、e of known torsional constant; the other end ofthe wire is fastened to a torsion head to impart a twist to thewire. The specimen is immersed in a chamber filled with a heattransfer medium at a specified uniform subnormal temperature.The torsion head is then twisted 180 and in turn twists thespecimen
10、 by an amount (less than 180) that is dependent onspecimen compliance or inverse stiffness. After a specifiedelapsed time, the amount of specimen twist is measured with amounted protractor. The angle of twist, which is inverselyrelated to the stiffness, is plotted versus the specified tempera-ture.
11、The temperature is then systematically increased inprescribed increments and the measurements repeated at eachtemperature, yielding a twist or inverse stiffness versus tem-perature profile for the test specimen. The torsional modulus ofthe specimen at any temperature is proportional to the quantity(
12、180-twist)/twist.4. Significance and Use4.1 These test methods may be used to determine thesubnormal temperature stiffening of flexible polymers or fab-rics coated with flexible polymers. Temperatures at which thelow temperature modulus is a specified multiple or ratio of themodulus at room temperat
13、ure are interpolated from the twistversus temperature curve. These specified ratios of low-temperature modulus to room-temperature modulus are calledrelative moduli. These temperatures at the relative moduliencompass the transition region between the glassy and rub-bery states of the materials teste
14、d.4.2 These test methods offer only a general guide to stiffnesscharacterization as service conditions of experimental materi-als may differ greatly from the test conditions.1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and Rubber-like Materials and are the direct res
15、ponsibility of SubcommitteeD11.10 on Physical Testing.Current edition approved Aug. 1, 2018. Published September 2018. Originallyapproved in 1943. Last previous edition approved in 2012 as D1053 92a (2012).DOI: 10.1520/D1053-92AR18.2For referenced ASTM standards, visit the ASTM website, www.astm.org
16、, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis internation
17、al standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee
18、.15. Apparatus5.1 Torsion Apparatus3The torsion apparatus (Fig. 1)shall consist of a torsion head, A, capable of being turned 180angular degrees in a plane normal to the torsion wire, B. Thetop of the wire shall be fastened to the torsion head passingthrough a loosely fitting sleeve, C. The bottom o
19、f the wire shallbe fastened to the test specimen clamp stud, D, by means of ascrew connector, E. A pointer, F, and movable protractor, G,shall be provided to permit convenient twist angle measure-ment and exact adjustment of the zero point.5.2 StandThe torsion apparatus shall be clamped to thesuppor
20、ting stand, H. It is advantageous to make the verticalportion of the stand from a poor thermal conductor.4The baseof the stand should be of stainless steel or other corrosion-resisting material.5.3 Torsion Wires Torsion wires, made of tempered springwire, shall be 65 6 8 mm (2.56 0.2 in.) long and h
21、avetorsional constants () of 0.0125, 0.05, and 0.2 mNm/ oftwist. The color codes for these wires are black, yellow, andwhite, respectively. The 0.05 mNm/ wire (color code yellow)shall be considered standard.5.4 Test Specimen RackA rack, I, made of a poor thermalconductor,4shall be provided for holdi
22、ng the test specimen, J,in a vertical position in the heat transfer medium (coolant). Therack shall be constructed to hold several test specimens; racksproviding spaces for five or ten test specimens are commonlyused. The rack shall be clamped to the stand, H. Two clamps,also made of a poor thermal
23、conductor, shall be provided forholding each test specimen. The faces of these clamps shall be6.4-mm (0.25-in.) width to facilitate proper contact with eachend of the wider test specimens, that is, Type B or Type Cspecimens. The distance between the top and bottom clampsshall be 25 6 2.5 mm (1.0 6 0
24、.1 in.) for Test MethodAand 386 2.5 mm (1.5 6 0.1 in.) for Test Method B. The bottomclamp, K, shall be a fixed part of the test specimen rack. Thetop clamp, L, shall act as an extension of the test specimen andshall not touch the rack while the specimen is being twisted.Clearance between the top of
25、the test specimen rack and thetest specimen clamp stud is assured by inserting thin spacersbetween the two (Note 1). The top clamp shall be secured to astud, D, which in turn shall be connected to the screwconnector, E.NOTE 1Slotted TFE-fluorocarbon spacers about 1.3 mm (0.050 in.)thick and 13 mm (0
26、.5 in.) wide have been found satisfactory. At lowtemperatures the test specimens stiffen in position and the spacers areremoved prior to test without losing the clearance.5.5 Temperature Measuring DeviceA thermocouple orthermometer shall be used. Copper-constantan thermocouples,used in conjunction w
27、ith a millivoltmeter or digital temperatureindicator, are highly satisfactory. The thermometer, if used,shall be calibrated in 1C divisions and shall have a range fromapproximately 70 to + 23C (95 to + 73.4F). The thermo-couple or the thermometer bulb shall be positioned as nearlyequidistant from al
28、l test specimens as possible, and equidistantbetween the top and the bottom of the test specimens.5.6 Heat Transfer MediaThe heat transfer medium shallbe either liquid or gaseous.Any material which remains fluid atthe test temperatures and does not affect the materials beingtested may be used. Among
29、 the liquids that have been foundsuitable for use are acetone, methyl alcohol, ethyl alcohol,butyl alcohol, silicone fluids, and normal hexane. Carbondioxide or air are the commonly used gaseous media. Vapors ofliquid nitrogen are useful for testing at very low temperatures.NOTE 2Specifications for
30、materials or products requiring tests usingthis standard should specifically state which coolant media are acceptablefor use in this test.5.7 Temperature ControlSuitable means, automatic ormanual, shall be provided for maintaining a uniform tempera-ture of the heat transfer medium within 61.0C (1.8F
31、) forboth liquid and gaseous media (Note 3).5.8 Tank or Test ChamberA tank for liquid heat transfermedia or a test chamber for gaseous media shall be provided.NOTE 3Liquid medium immersion baths, low-temperature cabinets,and means for controlling temperature are described in Practice D832.5.9 Stirre
32、r or FanA stirrer for liquids or a fan or blowerfor air, which ensures thorough circulation of the heat transfermedium, shall be provided.3The original apparatus was described and typical examples of the results of itsuse were given in a paper by Gehman, Woodford, and Wilkinson, Industrial andEngine
33、ering Chemistry, IECHA, Vol 39, September 1947, p. 1108.4Phenolic laminate sheet has been found satisfactory for this purpose.A Torsion head G Movable protractorB Torsion wire H Supporting standC Sieve I Specimen rackD Clamp stud J Test specimenE Screw connector K Bottom clampF Pointer L Top clampFI
34、G. 1 Schematic Drawing of Apparatus for Low-TemperatureStiffness TestD1053 92a (2018)25.10 TimerA stop watch or other timing device calibratedin seconds shall be provided.6. Test Specimens6.1 Test Method AThe test specimens shall be cut with asuitable die and shall be either TypeAstrips 40 6 2.5 mm
35、(1.56 0.1 in.) long and 3.0 6 0.2 mm (0.125 6 0.008 in.) wide orType B specimens of the type illustrated in Fig. 2. The standardthickness of the specimens shall be the thickness of thematerial undergoing test, but shall be not less than 1.5 mm(0.060 in.) nor greater than 2.8 mm (0.11 in.), and thedi
36、fference between maximum and minimum thickness of eachspecimen shall not exceed 0.08 mm (0.003 in.). Values ofthickness other than standard may be used provided it can beshown that they give equivalent results for the material beingtested. When specimens taken from the finished article are notof sta
37、ndard thickness, it should be permissible, upon agreementbetween the manufacturer and the purchaser, to use a standard-size specimen, taken from a certified press-cured sheet of thesame compound.6.2 Test Method BThe test specimens (Type C) shall becut with a suitable die so that the longer dimension
38、 is parallelto one of the diagonals of the fabric (on the bias). The testspecimen shall be a minimum of 44 mm (1.75 in.) long and 6.36 0.2 mm (0.250 6 0.008 in.) wide. The standard thickness ofthe specimen shall be the thickness of the material undergoingtest. The length of the test specimen shall b
39、e trimmed to fit inthe specimen clamps for test.7. Calibration of Torsion Wire7.1 Insert one end of the torsion wire in a vertical position,in a fixed clamp, and attach the lower end of the wire at theexact longitudinal center of a circular cross-section rod ofknown dimension and weight. For standar
40、dization purposes, itis suggested that the rod be 200 to 250 mm (8 to 10 in.) longand about 6 mm (0.25 in.) in diameter. Initially, the rod shouldnot be twisted through more than 90. The rod should beallowed to oscillate freely in a horizontal plane and the timerequired for 20 oscillations noted in
41、seconds. (An oscillationincludes the swing from one extreme to the other and return.)7.2 Calculate the torsional constant as follows: 5 2ml2/3 T2(1)where: = restoring force exerted by the wire, Nm/rad of twist,T = period of one oscillation, s,m = mass, kg, andl = length, m.7.3 The torsion wires shou
42、ld calibrate within 63 % of theirspecified torsional constants as given in 5.3.NOTE 4K = 17.45, where: K = torsional constant in mNm/.8. Number of Specimens8.1 Unless otherwise specified in the detailed specification,two specimens from each test unit shall be tested. It is goodpractice, however, to
43、include a control specimen with knownstiffness-temperature characteristics.9. Mounting Test Specimens9.1 Test Method AClamp the specimens in the testingapparatus in such a manner that 25 6 2.5 mm (1.0 6 0.1 in.)of each specimen is free between the clamps. For Type Bspecimens (see Fig. 2), make certa
44、in that the tab ends arecompletely within the clamps.9.2 Test Method BClamp the specimens in the testingapparatus in such a manner that 38.0 6 2.5 mm (1.5 6 0.1 in.)of each specimen is free between the clamps.10. Procedure for Stiffness Measurements in LiquidMedia10.1 Place the rack containing the t
45、est specimens in theliquid bath with a minimum of 25 mm (1 in.) of liquid coveringthe test specimens. Adjust the bath temperature to 23 6 3C(73.4 6 5F). Connect one of the specimens to the torsion headby means of the screw connector and the standard 0.05 mNm/wire. The spacer which provides clearance
46、 between the speci-men rack and the specimen clamp stud need not be used formeasurements made at room temperature. Adjust the pointerreading to zero by rotating the protractor scale. Turn the torsionhead quickly but smoothly 180. After 10 s as indicated by thetimer, record the pointer reading. If th
47、e reading at 23C(73.4F) does not fall in the range from 120 to 170, thestandard torsion wire is not suitable for testing the specimen.Specimens twisting more than 170 shall be tested with a wire(black) having a torsional constant of 0.0125 mNm/ of twist.Specimens twisting less than 120 shall be test
48、ed with a wire(white) having a torsional constant of 0.2 mNm/ of twist.10.2 Return the torsion head to its initial position anddisconnect the specimen. Then move the test specimen rack tobring the next test specimen into position for measurement(Note 5).All test specimens in the rack shall be measur
49、ed at 236 3C (73.4 6 5F).NOTE 5A modified version of the standard apparatus is now in use inwhich the rack is stationary while the torsion head is movable and can bepositioned over the several test specimens in turn.10.3 Insert the spacers between the specimen rack and thespecimen clamp studs. Adjust the liquid bath to the lowesttemperature desired (Note 6). After this temperature hasremained constant within 6 1C (6 1.8F) for 5 min, removeone spacer and test one specimen in the same manner as wasused at room temperature.
