1、Designation: D5279 08D5279 13Standard Test Method forPlastics: Dynamic Mechanical Properties: In Torsion1This standard is issued under the fixed designation D5279; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the use of dynamic mechanical instrumentation for gathering and reporting the viscoelasticproperties
3、 of thermoplastic and thermosetting resins and composite systems in the form of rectangular specimens molded directlyor cut from sheets, plates, or molded shapes. The torsional data generated may be used to identify the thermomechanical propertiesof a plastics material or composition.1.2 This test m
4、ethod is intended to provide means for determining the torsional modulus of plastics as a function of temperatureusing nonresonant forced-vibration techniques, as outlined in Practice D4065. Plots of the elastic (storage), loss (viscous), andcomplex moduli and tan delta, as a function of frequency,
5、time, or temperature are indicative of significant transitions in thethermomechanical performance of the polymeric material system.1.3 This test method is valid for a wide range of frequencies, typically from 0.01 to 100 Hz.1.4 Apparent discrepancies may arise in results obtained under differing exp
6、erimental conditions. These apparent differencesfrom results observed in another study can usually be reconciled without changing the observed data by reporting in full (asdescribed in this test method) the conditions under which the data were obtained.1.5 Test data obtained by this test method are
7、relevant and appropriate for use in engineering design.1.6 The values stated in SI units are to be regarded as standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropr
8、iate safety and health practices and determine the applicability of regulatorylimitations prior to use.NOTE 1This test method is equivalent to ISO 6721, Part 7.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD4065 Practice for Plastics: Dynamic Mechanica
9、l Properties: Determination and Report of ProceduresD4092 Terminology for Plastics: Dynamic Mechanical Properties3. Terminology3.1 For definitions applicable to this test method, refer to Terminology D4092.4. Summary of Test Method34.1 This test method covers the determination of the shear modulus o
10、f plastics using dynamic mechanical techniques. A testspecimen of rectangular cross section is tested in dynamic torsion. The specimen is gripped longitudinally between two clamps.The specimen of known geometry is placed in mechanical torsional displacement at either a fixed frequency, or variablefr
11、equencies at either isothermal conditions, or with a linear temperature increase. The elastic or loss modulus, or both, of thepolymeric material system are measured in torsion.1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommit
12、tee D20.10 on Mechanical Properties.Current edition approved March 1, 2008Sept. 1, 2013. Published April 2008Septmeber 2013. Originally approved in 1992. Last previous edition approved in 20012008as D5279 - 01.D5279 - 08. DOI: 10.1520/D5279-08.10.1520/D5279-13.2 For referencedASTM standards, visit t
13、heASTM 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.3 The particular method for measurement of the elastic and loss moduli and tan delta depends upon th
14、e individual instruments operating principles.This document is not 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
15、, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive
16、, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This test method provides a simple means of characterizing the thermomechanical behavior of plastics materials using verysmall amounts of material. The data obtained may be used for quality control, research an
17、d development, and establishment ofoptimum processing conditions.5.2 Dynamic mechanical testing provides a sensitive method for determining thermomechanical characteristics by measuringthe elastic and loss moduli as a function of frequency, temperature, or time. Plots of moduli and tan delta of a ma
18、terial versustemperature provide graphical representations indicative of functional properties, effectiveness of cure (thermosetting resinsystem), and damping behavior under specified conditions.5.3 This test method can be used to assess5.3.1 The modulus as a function of temperature,5.3.2 The modulu
19、s as a function of frequency,5.3.3 The effects of processing treatment, including orientation,5.3.4 Relative resin behavioral properties, including cure and damping,5.3.5 The effects of substrate types and orientation (fabrication) on elastic modulus, and5.3.6 The effects of formulation additives th
20、at might affect processability or performance.5.4 Before proceeding with this test method, reference should be made to the specification of the material being tested.Any testspecimen preparation, conditioning, dimensions, or testing parameters, or combination thereof, covered in the relevant ASTMmat
21、erials specification shall take precedence over those mentioned in this test method. If there are no relevant ASTM materialsspecifications, then the default conditions apply.6. Interferences6.1 Since small test specimen geometries are used, it is essential that the specimens be representative of the
22、 material beingtested.7. Apparatus7.1 The function of the apparatus is to hold a rectangular test specimen so that the material acts as the elastic and dissipativeelement in a mechanically driven torsional system. Dynamic mechanical instruments operate at a forced, constant amplitude, andeither at a
23、 fixed frequency, or variable frequencies.7.2 The apparatus shall consist of the following:7.2.1 Fixed MemberA fixed or essentially stationary member carrying one grip.7.2.2 Movable MemberA movable member carrying a second grip.7.2.3 GripsGrips for holding the test specimen between the fixed member
24、and the movable member. The grips shall bemechanically aligned, that is, they shall be attached to the fixed and movable member, respectively, in such a manner that they willmove into alignment as soon as any load is applied, so that the long axis of the test specimen will coincide with the directio
25、n ofthe applied pull through the center line of the grip assembly.7.2.3.1 The test specimen shall be held in such a way that slippage relative to the grips is minimized.7.2.4 Deformation (Strain Device)A device for applying a continuous linear deformation (strain) to the specimen. In theforce-displa
26、cement device the deformation (strain) is applied and then released. (See Table 1 of Practice D4065.)7.2.5 DetectorsDevices for determining dependent and independent experimental parameters, such as force (stress),deformation (strain), frequency, and temperature.Temperature should be measurable with
27、 a precision of61C, frequency to61 %,and force to 61 %.7.2.6 Temperature Controller and OvenAdevice for controlling the temperature, either by heating (in steps or ramps), cooling(in steps or ramps), maintaining a constant specimen environment, or a combination thereof. A temperature controller shou
28、ld besufficiently stable to permit measurement of environmental chamber temperature to within 1C.7.3 Nitrogen or other inert gas supply for purging purposes.8. Test Specimens8.1 The specimens may be cut from sheets, plates or molded shapes, or may be molded to the desired finished dimensions.Anyrect
29、angular specimen, representative of the material being tested and within the fixturing capabilities of the specific test instrumentbeing used, may employed, shall be used asso long as it an accurate description of the specimen is clearly stated in the test report.NOTE 2The test specimens may be cut
30、from sheets, plates, or molded shapes, or may be molded to the desired finished dimensions.9. Calibration9.1 Calibrate the instrument using procedures recommended by the manufacturer.D5279 13210. Conditioning10.1 ConditioningCondition the test specimens at 23.0 6 2.0C and 50 6 5 % relative humidity
31、for not less than 40 h priorto testing in accordance with Procedure A of Practice D618, unless otherwise specified by the contract or relevant materialspecification.11. Procedure11.1 Use an untested specimen for each measurement. Measure the width and thickness of the specimen to the nearest 0.03 mm
32、at the center of the specimen and enter those dimensions into the test program using the instruments software.11.2 Clamp the test specimen between the movable and stationary members using shim stock, if necessary, to minimize slippagewithin the clamp.11.3 Preload the test specimen so that a positive
33、 normal force is maintained during the test. Monitor the normal force duringtesting to ensure adequate preloading.11.4 Measure the jaw separation between the movable and stationary members to the nearest 0.03 mm and enter that dimensioninto the test program using the instruments software.NOTE 3Tests
34、 may be conducted in several modes depending on the desired characterization requirements and the properties of interest. Generallythose modes include a strain sweep during which the temperature and frequency are maintained at constant values; a frequency sweep during which thetemperature and strain
35、 are maintained at constant values; a temperature sweep during which the strain and frequency are maintained at constant valuesor a frequency-temperature sweep during which the strain is maintained at a constant value and properties are measured across a range of frequenciesat step increments of tem
36、perature.11.5 Based on the type of test being conducted:11.5.1 Select the frequency (or range of frequency) for dynamic-torsional displacement as desired.11.5.2 Select the torsional-displacement amplitude (or range of amplitude) as desired, making sure it is within the materialslinear elastic region
37、.NOTE 4An independent strain sweep test may need to be run to establish this property.11.5.3 Select the temperature (or range of temperature), dwell time and either ramp rate or step increments to be used iftemperature is to be varied.11.5.3.1 Temperature increases should be controlled to 1 to 2C/mi
38、n for linear increases or 2 to 5C/min (with a minimum of1-min thermal-soak time for step increases). These soak times should be set to assure thermal equilibrium of the test material.Appropriate soak times are generally related to the mass of the test specimen and to the ramp rate or step increment
39、being used.11.6 Conduct the desired test recording the appropriate data.12. Calculations12.1 The equations listed in Practice D4065 are used to calculate the important rheological properties measured in forced,nonresonant dynamic displacement:where:G = storage (elastic) modulus in torsion,G“ = loss
40、(viscous) modulus in torsion,G* = complex modulus in torsion, andd* = tan delta.13. Report13.1 Report the following information:13.1.1 Complete identification of the material tested, including type, source, manufacturers code, number, form, principaldimensions, and previous history as available,13.1
41、.2 Description and direction of cutting and loading specimen, including preload force,13.1.3 Conditioning procedure,13.1.4 Description of the instrument used for the test,13.1.5 Description of the calibration procedure,13.1.6 Identification of the sample atmosphere by gas composition, purity, and ra
42、te used,13.1.7 Width and thickness of specimen,13.1.8 Jaw separation distance,13.1.9 Frequency of dynamic displacement,13.1.10 Amplitude of displacement,13.1.11 Thermal gradient; heating rate,13.1.12 Number of specimens tested,D5279 13313.1.13 Table of data including moduli, tan delta, frequency, st
43、rain, and temperature as appropriate, and13.1.14 A plot of the modulus (moduli) and tan delta as appropriate. (See Fig. 1.)14. Precision and Bias14.1 The repeatability standard deviation has been determined for the following materials. Laboratory A evaluated apolyurethane sample and the values in Ta
44、ble 1 were obtained with the same test method in the same laboratory by the same operatorusing the same equipment in the shortest practical period of time using test specimens taken at random from a single quantity ofhomogeneous material. Laboratory B tested the same material and obtained the result
45、s shown in Table 1.15. Keywords15.1 dynamic mechanical rheological properties; elastic; loss; storage; tan delta; torsional shear modulus; viscoelastic behavior;viscousFIG. 1 Dynamic Mechanical Modulus in Torsion as a Function of TemperatureD5279 134SUMMARY OF CHANGESCommittee D20 has identified the
46、 location of selected changes to this standard since the last issue(D5279 - 01)(D5279 - 08) that may impact the use of this standard. (March(September 1, 2008)2013)(1) Revised 1.2,Section 8.18, 10.1,to 11.1,reduce 11.2,permissive 11.3, language.11.4, 11.5, 13.1.1, 13.1.13, and 13.1.14.(2) Added subs
47、ectionsNote 2 5.4, 11.5.1, 11.5.2, 11.5.3, 11.5.3.1, and 11.6.renumbered subsequent notes.(3) Deleted old subsections 11.7, 11.8, 13.1.13.(4) Reworded Note 1 to meet D4968 guidelines.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any ite
48、m mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical comm
49、ittee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM
