1、Designation: D1053 92a (Reapproved 2012)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 Department of Defense.1. Scope1.1 T
3、hese 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.1.2
4、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 address a
5、ll 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. Referenced Documents2.1 ASTM Standards:2D832 Practice for R
6、ubber 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, of the stiffening of flexible polymers.3.2 T
7、est 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 wire of known torsional constant; the other end
8、 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 by an amount (less than 180) that is depend
9、ent 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. The temperature is then systematically incre
10、ased 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(180-twist)/twist.4. Significance and Use4.1
11、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 temperature are interpolated from the twistversus te
12、mperature 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 tested.1These test methods are under the jurisdic
13、tion of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.14 on Time andTemperature-Dependent Physical Properties.Current edition approved Dec. 1, 2012. Published February 2013. Originallyapproved in 1943. Last previous edition approved in 2007 as D1053 92a (2007).DOI
14、: 10.1520/D1053-92AR12.2For 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.Copyright ASTM International, 100 Barr
15、 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 These test methods offer only a general guide to stiffnesscharacterization as service conditions of experimental materi-als may differ greatly from the test conditions.5. Apparatus5.1 Torsion Apparatus3The torsion appara
16、tus (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 of the wire shallbe fastened to the test specimen clamp
17、 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 thesupporting stand, H. It is advantageous to make the vertical
18、portion 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 havetorsional constants () of 0.0125, 0.05, and 0.2 mNm
19、/ 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 holding the test specimen, J,in a vertical position in the
20、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 conductor, shall be provided forholding each test spec
21、imen. 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 0.1 in.) for Test MethodAand 386 2.5 mm (1.5 6 0.1 in.)
22、 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 the test specimen rack and thetest specimen clamp stud
23、 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 (0.5 in.) wide have been found satisfactory. At lowtempe
24、ratures 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 with a millivoltmeter or digital temperatureindicator,
25、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 all test specimens as possible, and equidistantbetween t
26、he 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 the liquids that have been foundsuitable for use are
27、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 materials or products requiring tests usingthis standa
28、rd 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) forboth liquid and gaseous media (Note 3).5.8 Tank o
29、r 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 D832.3The original apparatus was described and typical examples of th
30、e results of itsuse were given in a paper by Gehman, Woodford, and Wilkinson, Industrial andEngineering 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
31、I Specimen rackD Clamp stud J Test specimenE Screw connector K Bottom clampF Pointer L Top clampFIG. 1 Schematic Drawing of Apparatus for Low-TemperatureStiffness TestD1053 92a (2012)25.9 Stirrer or Fan A stirrer for liquids or a fan or blowerfor air, which ensures thorough circulation of the heat t
32、ransfermedium, shall be provided.5.10 TimerA stop watch or other timing device calibratedin seconds shall be provided.6. Test Specimens6.1 Test Method A The test specimens shall be cut with asuitable die and shall be either TypeAstrips 40 6 2.5 mm (1.56 0.1 in.) long and 3.0 6 0.2 mm (0.125 6 0.008
33、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 thedifference between maximum and minimum thickness of ea
34、chspecimen 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 standard thickness, it should be permissible, upon agre
35、ementbetween 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 B The test specimens (Type C) shall becut with a suitable die so that the longer dimension is parallelto one of the diagonals of the fabric (
36、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 be trimmed to fit inthe specimen clamps for test.7.
37、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 standardization purposes, itis suggested that the rod be 2
38、00 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 seconds. (An oscillationincludes the swing from one
39、 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 should calibrate within 63 % of theirspecified torsiona
40、l 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 include a control specimen with knownstiffness-temp
41、erature characteristics.9. Mounting Test Specimens9.1 Test Method A Clamp 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 certain that the tab ends arecompletely within the clam
42、ps.9.2 Test Method B Clamp 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 test specimens in theliquid bath with a minimum of
43、 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 between the speci-men rack and the specimen clam
44、p 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 the reading at 23C(73.4F) does not fall in the rang
45、e 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 tested with a wire(white) having a torsional constant
46、 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 measured at 236 3C (73.4 6 5F).NOTE 5A modified version
47、 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 desire
48、d (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. Return the spacer to its originalposition after the specimen has been tested (Note 7).NOTE 6This varies with the type of m
49、aterial being tested since timeis saved by not starting at a temperature more than 10C (18F) lower thanFIG. 2 Type B SpecimenD1053 92a (2012)3the freezing point of the material. For natural rubber, the lowest tempera-ture required is usually 80C (112F); for styrene butadiene rubber, thelowest temperature is usually 70C (94F).NOTE 7Movement of the spacer often tends to alter the pointerposition with respect to the protractor; therefore, the pointer should beadjusted to zero after the spacer has been removed
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