1、Designation: D 1053 92a (Reapproved 2007)Standard Test Methods forRubber PropertyStiffening at Low Temperatures: FlexiblePolymers and Coated Fabrics1This standard is issued under the fixed designation D 1053; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case of revision, the 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.
3、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.1
4、.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 as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to ad
5、dress 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. Referenced Documents2.1 ASTM Standards:2D 832 Practi
6、ce for Rubber Conditioning For Low Tempera-ture TestingD 4483 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 polym
7、ers.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 wire of known torsional constant; the
8、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 by an amount (less than 180) that
9、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. The temperature is then systematica
10、lly 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(180-twist)/twist.4. Significance an
11、d 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 temperature are interpolated from the twist
12、versus 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 tested.4.2 These test methods offer only
13、 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 apparatus (Fig. 1)shall consist of a torsion head, A, capable of being turned 1801These test methods are under the
14、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, 2007. Published July 2007. Originally approvedin 1943. Last previous edition approved in 2001 as D1053 92a (2001)e
15、1.2For 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.3The original apparatus was described and typical examples
16、of the results of itsuse were given in a paper by Gehman, Woodford, and Wilkinson, Industrial andEngineering Chemistry, IECHA, Vol 39, September 1947, p. 1108.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.angular degrees in a plane
17、 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 stud, D, by means of ascrew connector, E. A pointer, F, and movable protractor, G,shall be provided
18、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 verticalportion of the stand from a poor thermal conductor.4The baseof the stand should be of stainless steel
19、 or other corrosion-resisting material.5.3 Torsion WiresTorsion wires, made of tempered springwire, shall be 65 6 8 mm (2.56 0.2 in.) long and havetorsional constants (k) 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/ w
20、ire (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 heat transfer medium (coolant). Therack shall be constructed to hold several test specimens; rackspro
21、viding 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 specimen. The faces of these clamps shall be6.4-mm (0.25-in.) width to facilitate proper contact with eac
22、hend 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.) for Test Method B. The bottomclamp, K, shall be a fixed part of the test specimen rack. Thetop clamp
23、, 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 is assured by inserting thin spacersbetween the two (Note 1). The top clamp shall be secured to astu
24、d, 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 lowtemperatures the test specimens stiffen in position and the spacers areremoved prior to test without losin
25、g the clearance.5.5 Temperature Measuring DeviceA thermocouple orthermometer shall be used. Copper-constantan thermocouples,used in conjunction with a millivoltmeter or digital temperatureindicator, are highly satisfactory. The thermometer, if used,shall be calibrated in 1C divisions and shall have
26、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 the top and the bottom of the test specimens.5.6 Heat Transfer MediaThe heat transfer medium shallbe e
27、ither 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 acetone, methyl alcohol, ethyl alcohol,butyl alcohol, silicone fluids, and normal hexane. Carbondioxi
28、de 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 standard should specifically state which coolant media are acceptablefor use in this test.5.7 Temperature C
29、ontrolSuitable 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 or Test ChamberA tank for liquid heat transfermedia or a test chamber for gaseous media shall be provi
30、ded.NOTE 3Liquid medium immersion baths, low-temperature cabinets,and means for controlling temperature are described in Practice D 832.5.9 Stirrer or Fan A stirrer for liquids or a fan or blowerfor air, which ensures thorough circulation of the heat transfermedium, shall be provided.5.10 TimerA sto
31、p 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 in.) wide orType B specimens of the type illustr
32、ated in Fig. 2. The standardthickness of the specimens shall be the thickness of the4Phenolic 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
33、clampF Pointer L Top clampFIG. 1 Schematic Drawing of Apparatus for Low-TemperatureStiffness TestD 1053 92a (2007)2material 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 eachspecimen shall
34、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 agreementbetween the
35、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 (on the bias). The
36、 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. Calibration of To
37、rsion 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 200 to 250 mm (8 t
38、o 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 extreme to the o
39、ther and return.)7.2 Calculate the torsional constant l as follows:l5p2ml2/3 T2(1)where:l = 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 torsional constants as
40、 given in 5.3.NOTE 4K = 17.45l, 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-temperature chara
41、cteristics.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 clamps.9.2 Test M
42、ethod 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 25 mm (1 in.
43、) 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 clamp stud need n
44、ot 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 range from 120 to
45、 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 of 0.2 mNm/
46、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 of the stand
47、ard 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). A
48、fter 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 material being
49、 tested since timeis saved by not starting at a temperature more than 10C (18F) lower thanthe 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.10.4 After all specimens have been tested at the lowesttemper
