ASTM E1356-2008(2014) Standard Test Method for Assignment of the Glass Transition Temperatures by Differential Scanning Calorimetry《采用差示扫描量热法分配玻璃转变温度的标准试验方法》.pdf

《ASTM E1356-2008(2014) Standard Test Method for Assignment of the Glass Transition Temperatures by Differential Scanning Calorimetry《采用差示扫描量热法分配玻璃转变温度的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM E1356-2008(2014) Standard Test Method for Assignment of the Glass Transition Temperatures by Differential Scanning Calorimetry《采用差示扫描量热法分配玻璃转变温度的标准试验方法》.pdf（4页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: E1356 08 (Reapproved 2014)Standard Test Method for Assignment of theGlass Transition Temperatures by Differential ScanningCalorimetry1This standard is issued under the fixed designation E1356; the number immediately following the designation indicates the year oforiginal adoption or, in

2、 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. Scope1.1 This test method covers the assignment of the glasstransition temperatures of mater

3、ials using differential scanningcalorimetry or differential thermal analysis.1.2 This test method is applicable to amorphous materials orto partially crystalline materials containing amorphous regions,that are stable and do not undergo decomposition or sublima-tion in the glass transition region.1.3

4、 The normal operating temperature range is from 120 to500C. The temperature range may be extended, dependingupon the instrumentation used.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 ISO standards 113572 is equivalent

5、 to this standard.1.6 This standard does not purport to address 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 u

6、se.2. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE473 Terminology Relating to Thermal Analysis and Rhe-ologyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE967 Test Method for Tempe

7、rature Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-lyzersE1142 Terminology Relating to Thermophysical Properties2.2 ISO Standards:3113572 Differential Scanning Calorimetry (DSC)-Part 2Determination of Glass Transition Temperature3. Terminology3.1 Definitions:3.1.1

8、 DefinitionsThe following terms are applicable tothis test method and can be found in Terminologies E473 andE1142: differential scanning calorimetry (DSC); differentialthermal analysis (DTA); glass transition; glass transitiontemperature (Tg); and specific heat capacity.3.2 Definitions of Terms Spec

9、ific to This Standard:3.2.1 There are commonly used transition points associatedwith the glass transition region(see Fig. 1).3.2.1.1 extrapolated end temperature, (Te), Cthe point ofintersection of the tangent drawn at the point of greatest slopeon the transition curve with the extrapolated baseline

10、 followingthe transition.3.2.1.2 extrapolated onset temperature, (Tf), Cthe pointof intersection of the tangent drawn at the point of greatestslope on the transition curve with the extrapolated baselineprior to the transition.3.2.1.3 inflection temperature, (Ti), Cthe point on thethermal curve corre

11、sponding to the peak of the first derivative(with respect to time) of the parent thermal curve. This pointcorresponds to the inflection point of the parent thermal curve.3.2.1.4 midpoint temperature, (Tm), Cthe point on thethermal curve corresponding to12 the heat flow differencebetween the extrapol

12、ated onset and extrapolated end.3.2.1.5 DiscussionMidpoint temperature is most com-monly used as the glass transition temperature (see Fig. 1).3.2.2 Two additional transition points are sometimes iden-tified and are defined: 3.2.2.1 temperature of first deviation, (To), Cthe point offirst detectable

13、 deviation from the extrapolated baseline prior tothe transition.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Calo-rimetry and Mass Loss.Current edition approved March 15, 2014. Published April 2014

14、. Originallyapproved in 1991. Last previous edition approved in 2008 as E1356 08. DOI:10.1520/E1356-08R14.2For 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 standa

15、rds Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.2.2 temper

16、ature of return to baseline, (Tr), Cthe pointof last deviation from the extrapolated baseline beyond thetransition.4. Summary of Test Method4.1 This test method involves continuously monitoring thedifference in heat flow into, or temperature between a referencematerial and a test material when they

17、are heated or cooled ata controlled rate through the glass transition region of the testmaterial and analyzing the resultant thermal curve to providethe glass transition temperature.5. Significance and Use5.1 Differential scanning calorimetry provides a rapid testmethod for determining changes in sp

18、ecific heat capacity in ahomogeneous material. The glass transition is manifested as astep change in specific heat capacity. For amorphous andsemicrystalline materials the determination of the glass transi-tion temperature may lead to important information about theirthermal history, processing cond

19、itions, stability, progress ofchemical reactions, and mechanical and electrical behavior.5.2 This test method is useful for research, quality control,and specification acceptance.6. Interferences6.1 Achange in heating rates and cooling rates can affect theresults. The presence of impurities will aff

20、ect the transition,particularly if an impurity tends to plasticize or form solidsolutions, or is miscible in the post-transition phase. If particlesize has an effect upon the detected transition temperature, thespecimens to be compared should be of the same particle size.6.2 In some cases the specim

21、en may react with air duringthe temperature program causing an incorrect transition to bemeasured. Whenever this effect may be present, the test shallbe run under either vacuum or an inert gas atmosphere. Sincesome materials degrade near the glass transition region, caremust be taken to distinguish

22、between degradation and glasstransition.6.3 Since milligram quantities of sample are used, it isessential to ensure that specimens are homogeneous andrepresentative, so that appropriate sampling techniques areused.7. Apparatus7.1 Differential Scanning CalorimeterThe essential in-strumentation requir

23、ed to provide the minimum differentialscanning calorimetric capability for this method includes a TestChamber composed of a furnace(s) to provide uniform con-trolled heating (cooling) of a specimen and reference to aconstant temperature or at a constant rate over the temperaturerange from 120 to 500

24、C, a temperature sensor to provide anindication of the specimen temperature to 60.1C, differentialsensors to detect heat flow difference between the specimenand reference with a sensitivity of 6W, a means of sustaininga test chamber environment of a purge gas of 10 to 100mL/min within 4 mL/min, a Te

25、mperature Controller, capableof executing a specific temperature program by operating thefurnace(s) between selected temperature limits at a rate oftemperature change of up to 20C/min constant to 60.5C/min.7.2 A Data Collection Device, to provide a means ofacquiring, storing, and displaying measured

26、 or calculatedFIG. 1 Glass Transition Region Measured TemperaturesE1356 08 (2014)2signals, or both. The minimum output signals required for DSCare heat flow, temperature and time.7.3 Containers, (pans, crucibles, vials, etc.) that are inert tothe specimen and reference materials and that are of suit

27、ablestructural shape and integrity to contain the specimen andreferences.7.4 For ease of interpretation, an inert reference materialwith an heat capacity approximately equivalent to that of thespecimen may be used. The inert reference material may oftenbe an empty specimen capsule or tube.7.5 Nitrog

28、en, or other inert purge gas supply, of purity equalto or greater than 99.9 %.7.6 Analytical Balance, with a capacity greater than 100 mg,capable of weighing to the nearest 0.01 mg.8. Specimen Preparation8.1 Powders or GranulesAvoid grinding if a preliminarythermal cycle as outlined in 10.2 is not p

29、erformed. Grinding orsimilar techniques for size reduction often introduce thermaleffects because of friction or orientation, or both, and therebychange the thermal history of the specimen.8.2 Molded Parts or PelletsCut the samples with amicrotome, razor blade, paper punch, or cork borer (size No. 2

30、or 3) to appropriate size in thickness or diameter, and lengththat will approximate the desired mass in the subsequentprocedure.8.3 Films or SheetsFor films thicker than 40 m, see 8.2.For thinner films, cut slivers to fit in the specimen tubes orpunch disks, if circular specimen pans are used.8.4 Re

31、port any mechanical or thermal pretreatment.9. Calibration9.1 Using the same heating rate, purge gas, and flow rate asthat to be used for analyzing the specimen, calibrate thetemperature axis of the instrument following the proceduregiven in Test Method E967.10. Procedure10.1 Use a specimen mass app

32、ropriate for the material to betested. In most casesa5to20mgmass is satisfactory. Anamount of reference material with a heat capacity closelymatched to that of the specimen may be used. An emptyspecimen pan may also be adequate.10.2 If appropriate, perform and record an initial thermalprogram in flo

33、wing nitrogen or air environment using a heatingrate of 10C/min to a temperature at least 20C above Tetoremove any previous thermal history. (See Fig. 1.)NOTE 1Other, preferably inert, gases may be used, and other heatingand cooling rates may be used, but must be reported.10.3 Hold temperature until

34、 an equilibrium as indicated bythe instrument response is achieved.10.4 Program cool at a rate of 20C/min to 50C below thetransition temperature of interest.10.5 Hold temperature until an equilibrium as indicated bythe instrument response is achieved.10.6 Repeat heating at same rate as in 10.2, and

35、record theheating curve until all desired transitions have been completed.Other heating rates may be used but must be reported.10.7 Determine temperatures Tm(preferred) Tf,orTi. (SeeFig. 1.)where:Tig= inflection temperature, CTf= extrapolated onset temperature, C, andTm= midpoint temperature, C.Incr

36、easing the heating rate produces greater baseline shiftsthereby improving detectability. In the case of DSC the signalis directly proportional to the heating rate in heat capacitymeasurements.NOTE 2The glass transition takes place over a temperature range andis known to be affected by time dependent

37、 phenomena, such as the rate ofheating (cooling). For these reasons, the establishment of a single numberfor the glass transition needs some explanation. Either Tfor Tmor Timaybe selected to represent the temperature range over which the glasstransition takes place. The particular temperature chosen

38、 must be agreedon by all parties concerned. In selecting which value should be taken asTg, the reader may wish to consider the following:(1)Tmwas found to have higher precision than Tf(see 12.3).(2) The measurement of Tfis often easier for those who construct therespective tangents by hand.(3)Tm(pre

39、ferred) or Tiis more likely to agree with the measurement ofTgby other techniques since it is constructed closer to the middle of thetemperature range over which the glass transition occurs.(4)Tfmay be taken to more closely represent the onset of thetemperature range over which the glass transition

40、occurs.Any comparisonof glass transition temperatures should contain a statement of how the testwas run and how the value was obtained.10.8 Recheck the specimen mass to ensure that no loss ordecomposition has occurred during the measurement.11. Report11.1 Report the following information:11.1.1 A co

41、mplete identification and description of thematerial tested.11.1.2 Description of instrument used for the test.11.1.3 Statement of the dimensions, geometry, and materialof the specimen holder.11.1.4 The scan rate in C/min.11.1.5 Description of temperature calibration procedure.11.1.6 Identification

42、of the specimen environment bypressure, gas flow rate, purity and composition, includinghumidity, if applicable.11.1.7 Results of the transition measurements using tem-perature parameters (Tg, etc.) cited in Fig. 1, or any combina-tion of parameters that were chosen.11.1.8 Tg(half extrapolated heat

43、capacity temperature) ispreferred.11.1.9 Any side reactions (for example, crosslinking, ther-mal degradation, oxidation) shall also be reported and thereaction identified, if possible.E1356 08 (2014)312. Precision and Bias412.1 Interlaboratory Test ProgramAn interlaboratorystudy for the determinatio

44、n of glass transition temperature asindicated by both the midpoint and the extrapolated onset wasconducted in 1984. Three polymeric materials were tested;polyurethane, polystyrene, and epoxy glass. Each of six par-ticipants tested four specimens of each material. (One did notreport test data on poly

45、urethane.) Practice E691 was followedfor the design and the analysis of the data.12.2 Test ResultThe precision information given below inCelsius degrees is for the comparison of two test results, eachof which is a single determination.12.3 Precision:DSC Determination of Tg:TfData95 % Limit, CMateria

46、l Tf, C Repeatability ReproducibilityPolyurethane 4.5 4.59 6.53Polystyrene 103.6 2.05 3.18Epoxy Glass 118.4 3.90 6.88DSC Determination of Tg:TmData95 % Limit, CMaterial Tm, C Repeatability ReproducibilityPolyurethane 12.2 2.24 4.15Polystyrene 106.3 1.85 2.02Epoxy Glass 123.0 2.77 5.17The above terms

47、 repeatability and reproducibility limit areused as specified in Practice E177. The respective standarddeviations among test results may be obtained by dividing thenumbers in the third and fourth columns by 2.8.12.4 The bias for these measurements is undeterminedbecause there are no reference values

48、 available for the mate-rials used.13. Keywords13.1 differential scanning calorimetry (DSC); differentialthermal analysis (DTA); glass transition; specific heat capacityASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin

49、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 committee 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 co