1、Designation: E1640 09E1640 13Standard 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, in the case of revi
2、sion, 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 assignment of a glass transition temperature (Tg)(Tg) of materials using
3、 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 upon the instrumentat
4、ion used, but, in order toencompass all materials, the minimum temperature should be about 150 C.about 150C.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 standard. No other units of
5、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 change.1.7 This standard d
6、oes 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 and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Stan
7、dards: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 Temperature Calibration of Thermomechanical AnalyzersE1545
8、 Test Method for Assignment of the Glass Transition Temperature by Thermomechanical AnalysisE1867 Test Method for Temperature Calibration of Dynamic Mechanical AnalyzersE2254 Test Method for Storage Modulus Calibration of Dynamic Mechanical AnalyzersE2425 Test Method for Loss Modulus Conformance of
9、Dynamic Mechanical Analyzers2.2 Other Standards:IEC 61006 Methods of Test for the Determination of the Glass Transition Temperature of Electrical Insulating Materials33. Terminology3.1 Definitions:3.1.1 Specific technical terms used in this document are defined in Terminology D4092 and E1142 includi
10、ng Celsius, dynamicmechanical analyzer, glass transition, glass transition temperature, loss modulus, storage modulus, tangent delta, and viscoelas-ticity.1 This test method is under the jurisdiction ofASTM Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.10
11、 on Fundamental,Statistical and Mechanical Properties.Current edition approved Sept. 1, 2009Aug. 1, 2013. Published October 2009August 2013. Originally approved in 1994. Last previous edition approved in 20042009 asE1640 04.E1640 09. DOI: 10.1520/E1640-09.10.1520/E1640-13.2 For referencedASTM standa
12、rds, 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.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor
13、, New York, NY 10036, http:/www.ansi.org.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, AST
14、M 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.2 d
15、ynamic mechanical analyzerany of various commercial or experimental devices used to study the viscoelastic responseof a specimen under a forced or free resonant oscillatory load. The force may be applied in torsion, flexure, or a combination oftension and compression.4. Summary of Test Method4.1 A s
16、pecimen 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 heating, the glasstransition region is marked by a rapid decrease in
17、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 glassy to a rubbery solid.5. Significance and Use5.1 This test method ca
18、n 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 function of temperature andfrequency, providing a means to quantify
19、these changes. In ideal cases, the temperature of the onset of the decrease in storagemodulus marks the glass transition.5.3 A glass transition temperature (Tg) is useful in characterizing many important physical attributes of thermoplastic,thermosets, and semi-crystalline materials including their
20、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.5.4 This test method is useful for quality control, spe
21、cification acceptance, and research.6. Interferences6.1 Because the specimen size will usually be small, it is essential that each specimen be homogeneous and/oror representativeof the material as a whole.whole, or both.6.2 An increase or decrease in heating rates from those specified may alter resu
22、lts.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 predetermined frequency shift factor
23、 or assuming the frequency shift factor of about 8 C8C per decade offrequency.4 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 in a mechanically oscillated sys
24、tem. Dynamic mechanical analyzers typically operate in one of several modes.See Table 1.7.2 The apparatus shall consist of the following:7.2.1 Clamps, a clamping arrangement that permits gripping of the specimen. Samples may be mounted by clamping at bothends (most systems), one end (for example, to
25、rsional pendulum), or neither end (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
26、 in forced vibrationdevices.4 Ferry, D. “Viscoelastic Properties of Polymers,” John Wiley dec = decaying amplitude; forced = forced oscillation;CA = constant amplitude; res = resonant frequency; fix = fixed frequency;CS = controlled stress.E1640 1327.2.3 Detector, for determining the dependent and i
27、ndependent experimental parameters, such as force (or stress), displacement(or strain), frequency, and temperature. Temperatures should be measurable with an accuracy of 60.5 C, 60.5C, force to 61 %,and frequency to 60.1 Hz.7.2.4 Temperature Controller and Oven, for controlling the specimen temperat
28、ure, either by heating, cooling (in steps or ramps),or by maintaining a constant experimental environment. The temperature programmer shall be sufficiently stable to permitmeasurement of specimen temperature to 60.5C. The precision of the required temperature measurement is 61.0 C.61.0C.7.2.5 Data C
29、ollection Device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or both.The minimum output signals require for dynamic mechanical analysis are storage modulus, loss modulus, tangent delta,temperature and time.NOTE 1Some instruments suitable for this test ma
30、y display only linear or logarithm storage modulus while others may display either linear and/ororlogarithm storage modulus. modulus, or both. Care must be taken to use the same modulus scale when comparing unknown specimens, and in thecomparison of results from one instrument to another.7.3 Nitroge
31、n, Helium or other gas supplied for purging purposes.7.4 Calipers or other length measuring device capable of measuring dimensions (or length within)6 0.01within) 60.01 mm.8. Precautions8.1 Toxic and corrosive, or both, effluents may be released when heating some materials and could be harmful to pe
32、rsonnel andto apparatus.8.2 Multiple TransitionsUnder 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
33、, the motion of groups pendent to the main backbone 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, suc
34、h treatment should be noted in the report.reported.9.2 Due to the numerous types of dynamic mechanical analyzers, sample size is not fixed by this test method. In many cases,specimens measuring between 1 5 20 mm and 1 10 50 mm are suitable.NOTE 2It is important to select a specimen size appropriate
35、for both the material and the testing apparatus. 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 storage modulus modulus, loss modules, and temperature signals in accordance withTest M
36、ethods E1867 and, 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 viscoe
37、lastic range of the material. Strains of less than 1 % arerecommended and should not exceed 5 %.11.4 Conduct tests at a heating rate of 1 C/min 1C/min and a frequency of 1 Hz. Other heating rates and frequencies may beused but shall be reported.NOTE 3The glass transition temperature measured by dyna
38、mic 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
39、is 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 8 C 8C for a typical amorphous material. The effect of these variableson the temperature of the tangent delta peak may be observed by r
40、unning specimens at two or more rates and comparing the results (see AppendixX1appendix).).NOTE 4Where possible in automated systems, a minimum of one data point should be collected for each C increase in temperature.At low and highfrequencies, use care in the selection of scanning rate and frequenc
41、y 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 Ceach C increase in temperature.11.5 Measure and record t
42、he storage modulus, from 30 C 30C below to 20 C 20C 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
43、region to the soft, rubbery region of the material under test.E1640 133NOTE 5Storage 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
44、and must be the 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 transit
45、ions.12.1.3 The temperature at which these tangent lines intersect is reported as the glass transition temperature, Tg (see Fig. 1).NOTE 6Under special circumstances agreeable to all parties, other temperatures taken from the storage modulus, loss modulus, or tangent delta curvemay be taken to repre
46、sent the temperature 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 Tl Tt .12.2 For fixed f
47、requency measurements at 1 Hz.12.2.1 Report the mean value of duplicate determinations as Tg .12.3 For measurements made at frequencies other than 1 Hz.12.3.1 Using a predetermined frequency shift factor (k) (see Appendix X1appendix),), calculate the first approximation of theglass transition temper
48、ature (Tl) using equation 1.Tl 5T1T2k logF1Hz (1)12.3.2 Calculate the glass transition temperature using equation 2:T15T1T T1 k log F1Hz (2)where:k = Predetermined Frequency Shift Factor (see Appendix X1.1)k = Predetermined Frequency Shift Factor (see Appendix X1)F = Frequency of Measurement (Hz)T =
49、 Glass Transition Temperature Observed at Frequency F (K)T = Glass Transition Temperature Observed at Frequency F (K)Tl = First Approximation for the Glass Transition Temperature at 1 Hz (K)Tl = First Approximation for the Glass Transition Temperature at 1 Hz (K)Tl = Glass Transition Temperature at 1 Hz (K)Tl = Glass Transition Temperature at 1 Hz (K)FIG. 1 Storage ModulusE1640 134Example:example:k = 12,417Kk = 12 417KF = 2 HzT = 100 C = 373KT = 100C = 373KT = 373K1373K! 373K!212,417K log25373K23.37KFIG. 2 Loss ModulusFIG. 3
