1、Designation: D6204 07D6204 12Standard Test Method forRubberMeasurement of Unvulcanized RheologicalProperties Using Rotorless Shear Rheometers1This standard is issued under the fixed designation D6204; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、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.1. Scope1.1 This test method covers the use of a rotorless oscillating shear rheometer for the measu
3、rement of the flow properties of rawrubber and unvulcanized rubber compounds. These flow properties are related to factory processing.1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.3 This standard does not purport to addre
4、ss all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1485 Practice fo
5、r Rubber from Natural SourcesSampling and Sample PreparationD1646 Test Methods for RubberViscosity, Stress Relaxation, and Pre-Vulcanization Characteristics (Mooney Viscometer)D3896 Practice for Rubber From Synthetic SourcesSamplingD5289 Test Method for Rubber PropertyVulcanization Using Rotorless C
6、ure MetersD6601 Test Method for Rubber PropertiesMeasurement of Cure and After-Cure Dynamic Properties Using a Rotorless ShearRheometer3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 complex shear modulus, G*, nthe ratio of peak amplitude shear stress to peak amplitude shear s
7、train; mathematically,G* = (S*/Area )/Strain = (G2 + G”2)1/2.3.1.2 complex torque, S*, nthe peak amplitude torque response measured by a reaction torque transducer for a sinusoidallyapplied strain; mathematically, S* is computed by S* = (S2 + S”2)1/2.3.1.3 dynamic complex viscosity *, nthe ratio of
8、the complex shear modulus, G* to the oscillation frequency, , in radiansper second.3.1.4 elastic torque, S, nthe peak amplitude torque component that is in phase with a sinusoidally applied strain.3.1.5 loss angle, , nthe phase angle by which the complex torque (S*) leads a sinusoidally applied stra
9、in.3.1.6 loss factor, tan , nthe ratio of loss modulus to storage modulus, or the ratio of viscous torque to elastic torque;mathematically, tan = G”/G = S”/S.3.1.7 loss shear modulus G”, nthe ratio of (viscous) peak amplitude shear stress to peak amplitude shear strain for the torquecomponent 90 out
10、 of phase with a sinusoidally applied strain; mathematically, G” = (S”/Area)/Peak Strain.3.1.8 real dynamic viscosity, , nthe ratio of the loss shear modulus, G” to the oscillation frequency, , in radians per second.3.1.9 storage shear modulus, G, nthe ratio of (elastic) peak amplitude shear stress
11、to peak amplitude shear strain for thetorque component in phase with a sinusoidally applied strain; mathematically, G = (S/Area)/Peak Strain.3.1.10 viscous torque, S”, nthe peak amplitude torque component, which is 90 out of phase with a sinusoidally applied strain.1 This test method is under the ju
12、risdiction of ASTM Committee D11 on Rubber and is the direct responsibility of Subcommittee D11.12 on Processability Tests.Current edition approved July 1, 2007Dec. 15, 2012. Published July 2007January 2013. Originally approved in 1997. Last previous edition approved in 20052007 asD6204 05.D6204 07.
13、 DOI: 10.1520/D6204-07.10.1520/D6204-12.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not
14、an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate.
15、 In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method4.1 A rubber test specimen is contained in a
16、 die cavity that is closed and maintained at an elevated temperature. The cavity isformed by two dies, one of which is oscillated through a rotary amplitude. This action produces a sinusoidal torsional strain in thetest specimen, resulting in a sinusoidal torque, which measures a viscoelastic qualit
17、y of the test specimen. The test specimen canbe either a raw natural or synthetic rubber or an uncured rubber compound.4.2 These viscoelastic measurements can be made based on (1) a frequency sweep, in which the frequency is programmed tochange in steps under constant strain amplitude and temperatur
18、e conditions, (2) a strain sweep, in which the strain amplitude isprogrammed to change in steps under constant frequency and temperature conditions, or (3) a temperature sweep, in which thetemperature is programmed to either increase or decrease under constant strain amplitude and frequency conditio
19、ns. A timed testmay also be performed in which a sinusoidal strain is applied for a given time period under constant strain amplitude, frequency,and temperature conditions.4.2.1 For a frequency sweep test, the instrument is typically programmed to increase the frequency with each subsequent stepchan
20、ge. For a strain sweep test, the instrument is usually programmed to increase the strain amplitude with each subsequent stepchange. This is done to minimize the influence of prior test conditions on subsequent test steps. For temperature sweeps, thetemperature may be programmed either to increase or
21、 decrease with each subsequent step change, depending on the effects to bestudied. The results from increasing frequency, strain amplitude, or temperature may not be the same as results from decreasingthese test parameters.4.3 Rheological properties are measured for each set of frequency, strain, an
22、d temperature conditions. These properties can bemeasured as combinations of elastic torque S, viscous torque S”, storage shear modulus G, loss shear modulus G”, tan , complexdynamic viscosity *, and real dynamic viscosity .4.4 This standard is organized in three different parts (A, B, and C), which
23、 can be run in the following combinations:ABA, BA, B, CA, CB, CC4.5 These three parts are described below:4.5.1 PartAis a rapid three-point frequency sweep performed at a low strain of 7 % to relate to differences in average molecularweight, molecular weight distribution, and long chain branching fo
24、r raw elastomers and to relate to differences in flowability, shearthinning, and die swell for mixed batches.4.5.2 Part B is a rapid two-point frequency sweep performed at a moderate strain of 100 % (or higher) to relate to gel differenceswith raw elastomers and to relate to differences in higher sh
25、ear rate viscosity and die swell for mixed batches. The higher appliedstrain is commonly needed to help break up gel structure in some raw elastomers and break up filler aggregate networks for mixedbatches. Although 100 % strain is the more common test condition, significantly higher test sensitivit
26、y is possible by performingthis frequency sweep at 200 % strain or higher.4.5.3 Part C is a linear ramped temperature rise from processing temperature (typically 100C) to cure temperature (usually 140,160, or 180C) in a predetermined time period. This ramped temperature cure is performed to enhance
27、statistical test sensitivityto real differences in scorch times providing better scorch control than traditional isothermal cure tests (Test Method D5289), andto provide a controlled transition from Part A or Part B tests, or both, in this method to a cure test.5. Significance and Use5.1 This test m
28、ethod is used to measure viscoelastic properties of raw rubber as well as unvulcanized rubber compounds. Theseviscoelastic properties may relate to factory processing behavior.5.2 This test method may be used for quality control in rubber manufacturing processes and for research and developmenttesti
29、ng of raw rubber and rubber compounds. This test method may also be used for evaluating compound differences resultingfrom the use of different compounding materials.6. Apparatus6.1 Torsion Strain Rotorless Oscillating Rheometer With a Sealed CavityThis type of rheometer measures the elastic torqueS
30、 and viscous torque S” produced by oscillating angular strain of set amplitude and frequency in a completely closed and sealedtest cavity.6.2 Sealed Die CavityThe sealed die cavity is formed by two conical surface dies. In the measuring position, the two dies arefixed a specified distance apart so t
31、hat the cavity is closed and sealed (see Fig. 1).6.3 Die GapFor the sealed cavity, no gap shall exist at the edges of the dies. At the center of the dies, the die gap shall beset at 0.45 6 0.05 mm.D6204 1226.4 Die Closing MechanismFor the sealed cavity, a pneumatic cylinder or other device shall clo
32、se the dies and hold themclosed during the test with a force not less than 11 kN (2500 lbf).6.5 Die Oscillating SystemThe die oscillating system consists of a direct drive motor that imparts a torsional oscillatingmovement to the lower die in the cavity plane.6.5.1 The oscillation amplitude can be v
33、aried, but a selection of 60.5 arc (7.0 % shear strain) is preferred for frequency sweeptests. The oscillation frequency can be varied between 0.03 and 30 Hz.6.6 Torque Measuring SystemThe torque measuring system shall measure the resultant shear torque.6.6.1 The torque measuring device shall be rig
34、idly coupled to one of the dies, any deformation between the die and device shallbe negligibly small, and the device shall generate a signal that is proportional to the torque. The total error resulting from zero pointerror, sensitivity error, linearity, and repeatability errors shall not exceed 1 %
35、 of the selected measuring range.6.6.2 The torque recording device shall be used to record the signal from the torque measuring device and shall have a responsetime for full scale deflection of the torque scale of 1 s or less. The torque shall be recorded with an accuracy of 60.5 % of therange. Torq
36、ue recording devices may include analog chart recorders, printers, plotters, or computers.6.6.3 A reference torque device is required to calibrate the torque measurement system. A torque standard shall be used tocalibrate the torque measuring system at the selected angular displacement by clamping a
37、 steel torsion rod to the oscillating andFIG. 1 Typical Sealed Torsion Shear Rotorless CuremeterD6204 123the torque measuring dies of the torsion shear rheometer (see Fig. 2). The reference values for angular displacement andcorresponding torque shall be established by the manufacturer for each torq
38、ue standard.6.7 Reference Test TemperatureThe standard reference test temperature shall be 100C (212F) or 125C (257F) forprocessability measurements. Tests may be carried out at other temperatures when appropriate.6.8 Temperature Control SystemThis system shall permit the set point temperature to be
39、 varied between 40C and 220C withan accuracy of 60.3C or better.6.8.1 The dies shall heat to the set point temperature in 1.0 min or less from closure of the test cavity. Once the initial heating-uptime has been completed, die temperature shall not vary by more than60.3C for the remainder of a test
40、at a set temperature.Whenthe set temperature is changed in a programmed temperature sweep (step changes in temperature), rheological measurements shallnot be recorded until the die temperatures are within 60.3C of the new set temperature for at least 30 s. When the set temperatureis set for a ramped
41、 increase as described in Part C of this test method, the temperature shall not overshoot by more than 3C withrecovery to within 60.3C within 1 min of control at the plateau temperature at the end of the temperature ramp.6.8.2 Temperature distribution within the test piece shall be as uniform as pos
42、sible. Within the deformation zone, a toleranceof 61C of the average test piece temperature shall not be exceeded.6.8.3 Die temperature is determined by a temperature sensor used for control. The difference between the die temperature andthe average test piece temperature shall not be more than 2C.
43、Temperature measurement accuracy shall be 60.3C for the dietemperature sensor.7. Test SpecimenSampling7.1 A test specimen taken from a The sample shall be between 5 and 6 cmtaken from 3 for the sealed cavity oscillatingrheometer. The specimen volume shall exceed the test cavity volume by a small amo
44、unt, to be determined by preliminary tests.Typically, specimen volume should be 130 to 150 % of the test cavity volume. Once a target weight for a desired volume a rawrubber or rubber compound as required by the mixing method or other sampling instructions. Condition a raw rubber sample inaccordance
45、 with Practice D1485 or Practice D3896has been established, specimen weights shall be controlled to within 60.5 gFIG. 2 Typical Torque Standard Calibration Devices for Torsion Shear CuremetersD6204 124for best repeatability. The initial test specimen shape shall fit well within the perimeter of the
46、test cavity. until it has reached roomtemperature (23 6 3C (73 6 5F) throughout.7.2 Raw Rubber SpecimensCondition the specimen obtained in accordance with Practice The sample shall be homogeneous,at D1485 or Practice D3896 until it has reached room temperature (23 6 3C (73 6 5F) throughout.Araw rubb
47、er test specimenroom temperature, and as free of air as possible. Raw rubber samples should be tested as received, that is unmassed (not milled).If the material cannot be tested unmassed, then follow the sample preparation section of Test Methods D1646. Rubber compoundsamples shall be in the form of
48、 a sheet. Rubber compounds with or without curatives may be tested using Parts A or B of thismethod. A vulcanizable rubber compound is required for Part C testing.7.2.1 Raw rubber test specimens in a sealed cavity oscillating rheometer must be pre-conditioned in the instrument beforerheological meas
49、urements are made to improve test precision. A programmed pre-conditioning step shall consist of oscillating thespecimen at 0.5 Hz, 62.8 % strain, 100C (or 125C) for the time interval specified in Table 1.7.3 Compounded Rubber SpecimensTest specimens shall be taken from a rubber compound as required by the mixing methodor other sampling instructions. Rubber compounds with or without curatives may be tested.The temperature of the sample and itsheat history can significantly affect test results.
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