ASTM E1640-2018 Standard Test Method for Assignment of the Glass Transition Temperature By Dynamic Mechanical Analysis.pdf

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1、Designation: E1640 13 (Reapproved 2018)E1640 18Standard Test Method forAssignment of the Glass Transition Temperature ByDynamic Mechanical Analysis1This standard is issued under the fixed designation E1640; 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.1. Scope Scope*1.1 This test method covers the assignment of a glass transition temperature (T

3、g) of materials using dynamic mechanicalanalyzers.1.2 This test method is applicable to thermoplastic polymers, thermoset polymers, and partially crystalline materials which arethermally stable in the glass transition region.1.3 The applicable range of temperatures for this test method is dependent

4、upon the instrumentation used, but, in order toencompass all materials, the minimum temperature should be about 150C. about 150 C.1.4 This test method is intended for materials having an elastic modulus in the range of 0.5 MPa to 100 GPa.1.5 The values stated in SI units are to be regarded as standa

5、rd. No other units of measurement are included in this standard.1.6 This standard is similar to IEC 61006 except that standard uses the peak temperature of the loss modulus peak as the glasstransition temperature while this standard uses the extrapolated onset temperature of the storage modulus chan

6、ge.1.6 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 appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations prior to us

7、e.1.7 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to

8、Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D4092 Terminology for Plastics: Dynamic Mechanical PropertiesE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1142 Terminology Relating to Thermophysical PropertiesE1363 Test Method for

9、Temperature Calibration of Thermomechanical AnalyzersE1545 Test Method for Assignment of the Glass Transition Temperature by Thermomechanical AnalysisE1867 Test Methods for Temperature Calibration of Dynamic Mechanical AnalyzersE2254 Test Method for Storage Modulus Calibration of Dynamic Mechanical

10、AnalyzersE2425 Test Method for Loss Modulus Conformance of Dynamic Mechanical AnalyzersE2877 Guide for Digital Contact Thermometers2.2 Other Standards:IEC 61006 Methods of Test for the Determination of the Glass Transition Temperature of Electrical Insulating Materials33. Terminology3.1 Definitions:

11、1 This test method is under the jurisdiction ofASTM Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.10 on Fundamental,Statistical and Mechanical Properties.Current edition approved March 15, 2018Aug. 1, 2018. Published March 2018August. Originally approved

12、in 1994. Last previous edition approved in 20132018 asE1640 13.E1640 13 (2018). DOI: 10.1520/E1640-13R18.10.1520/E1640-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refe

13、r to the standards Document Summary page on the ASTM website.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 cha

14、nges accurately, 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 Ba

15、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1 Specific technical terms used in this document are defined in Terminologies D4092 and E1142 including Celsius, dynamicmechanical analyzer, glass transition, glass transition temperature, loss modulus, storage modulus

16、, tangent delta, andviscoelasticity.4. Summary of Test Method4.1 Aspecimen of known geometry is placed in mechanical oscillation at either fixed or resonant frequency and changes in theviscoelastic response of the material are monitored as a function of temperature. Under ideal conditions, during he

17、ating, the glasstransition region is marked by a rapid decrease in the storage modulus and a rapid increase in the loss modulus and tangent delta.The glass transition of the test specimen is indicated by the extrapolated onset of the decrease in storage modulus which marksthe transition from a glass

18、y to a rubbery solid.5. Significance and Use5.1 This test method can be used to locate the glass transition region and assign a glass transition temperature of amorphousand semi-crystalline materials.5.2 Dynamic mechanical analyzers monitor changes in the viscoelastic properties of a material as a f

19、unction of temperature andfrequency, providing a means to quantify these changes. In ideal cases, the temperature of the onset of the decrease in storagemodulus marks the glass transition.5.3 The glass transition takes place over a temperature range. This method assigns a single temperature (Tg) to

20、represent thattemperature range as measured by dynamic mechanical analysis. Tg may be determined by a variety of techniques and may varyaccording to that technique.5.4 A glass transition temperature (Tg) is useful in characterizing many important physical attributes of thermoplastic,thermosets, and

21、semi-crystalline materials including their thermal history, processing conditions, physical stability, progress ofchemical reactions, degree of cure, and both mechanical and electrical behavior.Tg may be determined by a variety of techniquesand may vary in accordance with the technique.5.5 This test

22、 method is useful for quality control, specification acceptance, and research.6. Interferences6.1 Because the specimen size will usually be small, it is essential that each specimen be homogeneous or representative of thematerial as a whole, or both.6.2 An increase or decrease in heating rates from

23、those specified may alter results.6.3 A transition temperature is a function of the experimental frequency, therefore the frequency of test must always bespecified. (The transition temperature increases with increasing frequency.) Extrapolation to a common frequency may beaccomplished using a predet

24、ermined frequency shift factor or assuming the frequency shift factor of about 8C 8 C per decadeof frequency.3 Such extrapolation shall be reported.7. Apparatus7.1 The function of the apparatus is to hold a specimen of uniform dimension so that the sample acts as the elastic anddissipative element i

25、n a mechanically oscillated system. Dynamic mechanical analyzers typically operate in one of several modes.See Table 1.7.2 The apparatus shall consist of the following:3 Ferry, D., Viscoelastic Properties of Polymers, John Wiley dec = decaying amplitude;forced = forced oscillation; CA = constant amp

26、litude; res = resonant fre-quency; fix = fixed frequency; CS = controlled stress.Mode Mechanical ResponseTension Flexural Torsional CompressionFree/dec . . X .Forced/res/CA . X X .Forced/fix/CA X X X XForced/fix/CS X X . XFree = free oscillation; dec = decaying amplitude; forced = forced oscillation

27、;CA = constant amplitude; res = resonant frequency; fix = fixed frequency;CS = controlled stress.E1640 1827.2.1 Clamps, a clamping arrangement that permits gripping of the specimen. Samples may be mounted by clamping at bothends (most systems), one end (for example, torsional pendulum), or neither e

28、nd (free bending between knife edges).7.2.2 Oscillatory Stress (Strain), for applying an oscillatory deformation (strain) or oscillatory stress to the specimen. Thedeformation may be applied and then released, as in freely vibrating devices, or continuously applied, as in forced vibrationdevices.7.2

29、.3 Detector, for determining the dependent and independent experimental parameters, such as force (or stress), displacement(or strain), frequency, and temperature. Temperatures should be measurable with an accuracy of 60.5C, shall be readable towithin 60.1 C, force to 61 %, and frequency to 60.1 Hz.

30、NOTE 1The temperature sensor shall be placed as close as is practical, but not touching, the test specimen7.2.4 Temperature Controller and Oven, for controlling the specimen temperature, either by heating, cooling (in steps or ramps),or by maintaining a constant experimental environment. The tempera

31、ture programmer shall be sufficiently stable to permitmeasurement of specimen temperature to 60.5C. 60.5 C. The precision of the required temperature measurement is61.0C.61.0 C.7.2.5 Data Collection Device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or b

32、oth.The minimum output signals require for dynamic mechanical analysis are storage modulus, loss modulus, tangent delta,temperature and time.NOTE 2Some instruments suitable for this test may display only linear or logarithm storage modulus while others may display either linear orlogarithm storage m

33、odulus, or both. Care must be taken to use the same modulus scale when comparing unknown specimens, and in the comparison ofresults from one instrument to another.7.3 Nitrogen, Helium or other gas supplied for purging purposes.NOTE 3The same purge gas shall be used for calibration and measurement of

34、 the test specimen.7.4 Calipers or other length measuring device capable of measuring dimensions (or length within) 60.01 mm.8. Precautions8.1 Toxic and corrosive, or both, effluents may be released when heating some materials and could be harmful to personnel andto apparatus.8.2 Multiple Transition

35、sUnder some experimental conditions it is possible to have transitions secondary to the primary glasstransition. Secondary transitions may be related to the glass transition of a second polymeric phase, melt processes, crystallization,chemical reactions, the motion of groups pendent to the main back

36、bone or the crankshaft motion of the polymer backbone.9. Samples9.1 Samples may be any uniform size or shape, but are ordinarily analyzed in rectangular form. If some heat treatment is appliedto the specimen to obtain this preferred analytical form, such treatment should be reported.9.2 Due to the n

37、umerous types of dynamic mechanical analyzers, sample size is not fixed by this test method. In many cases,specimens measuring between 1 5 20 1 mm 5 mm 20 mm and 1 10 50 1 mm 10 mm 50 mm are suitable.NOTE 4It is important to select a specimen size appropriate for both the material and the testing ap

38、paratus. For example, thick samples may berequired for low modulus materials while thin samples may be required for high modulus materials.10. Calibration10.1 Calibrate the temperature, storage modulus, loss modules, and temperature signals in accordance with and loss modulussignals according to Tes

39、t Methods E1867, E2254, and E2425, respectively.11. Procedure11.1 Mount the specimen in accordance with procedure recommended by the manufacturer.11.2 Measure the length, width, and thickness of the specimen to an accuracy of 60.01 mm.11.3 Maximum strain amplitude should be within the linear viscoel

40、astic range of the material. Strains of less than 1 % arerecommended and should not exceed 5 %.11.4 Conduct tests at a heating rate of 1C/min 1 C/min and a frequency of 1 Hz. Other heating rates and frequencies may beused but shall be reported.NOTE 5The glass transition temperature measured by dynam

41、ic mechanical measurements is dependent upon heating rate and oscillatory frequency.The experimental heating rate and the frequency of oscillation should be slow enough to allow the entire specimen to reach satisfactory thermal andmechanical equilibration. When the heating rate or oscillatory rate i

42、s high, the experimental time scale is shortened, and the apparent Tg is raised.Changing the time scale by a factor of 10 will generally result in a shift of about 8C 8 C for a typical amorphous material. The effect of these variableson the temperature of the tangent delta peak may be observed by ru

43、nning specimens at two or more rates and comparing the results (see Appendix X1).NOTE 6Where possible in automated systems, a minimum of one data point should be collected for each C increase in temperature.At low and highE1640 183frequencies, use care in the selection of scanning rate and frequency

44、 rate; select test conditions and a data collection rate that will ensure adequateresolution of the mechanical response of the specimen. For example, select a heating rate that allows the specimen to complete at least one oscillationfor each C increase in temperature.11.5 Measure and record the stor

45、age modulus, from 30C 30 C below to 20C 20 C above the suspected glass transitionregion.12. Calculation12.1 For the purpose of this test method the glass transition shall be taken as the extrapolated onset to the sigmoidal change inthe storage modulus observed in going from the hard, brittle region

46、to the soft, rubbery region of the material under test.NOTE 7Storage modulus may be displayed on a linear or logarithmic scale. The reported glass transition temperature will differ depending upon thescale chosen. The scale type (for example, linear or logarithmic) shall be reported and must be the

47、same for all parties comparing results.12.1.1 Construct a tangent to the storage modulus curve below the transition temperature.12.1.2 Construct a tangent to the storage modulus curve at the inflection point approximately midway through the sigmoidalchange associated with the transitions.12.1.3 The

48、temperature at which these tangent lines intersect is reported as the glass transition temperature, Tg (see Fig. 1).NOTE 8Under special circumstances agreeable to all parties, other temperatures taken from the storage modulus, loss modulus, or tangent delta curvemay be taken to represent the tempera

49、ture range over which the glass transition takes place. Among these alternative temperatures are the peak of theloss modulus (Tl) or tangent delta (Tt) curves as illustrated in Fig. 2 and Fig. 3, respectively. These temperatures are generally in the order Tg 12 400 KX1.5 The frequency shift factor is a function of the material and should be determined individually. The frequency shift factorsfor many thermoplastics and thermosets are nominally 8C 8 C per decade of frequency change. Values for elastomers are usuallyhigher and may