ASTM E2160-2004(2018) Standard Test Method for Heat of Reaction of Thermally Reactive Materials by Differential Scanning Calorimetry.pdf

1、Designation: E2160 04 (Reapproved 2018)Standard Test Method forHeat of Reaction of Thermally Reactive Materials byDifferential Scanning Calorimetry1This standard is issued under the fixed designation E2160; 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. Scope1.1 This test method determines the exothermic heat ofreaction of thermally reactive c

3、hemicals or chemical mixtures,using milligram specimen sizes, by differential scanning calo-rimetry. Such reactive materials may include thermally un-stable or thermoset materials.1.2 This test method also determines the extrapolated onsettemperature and peak heat flow temperature for the exothermic

4、reaction.1.3 This test method may be performed on solids, liquids orslurries.1.4 The applicable temperature range of this test method is25 to 600C.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 There is no ISO method eq

5、uivalent to this standard.1.7 This standard is related to Test Method E537 and toNAS 1613, but provides additional information.1.8 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 a

6、ppro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for th

7、eDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE537 Test Method for The Thermal Stability of C

8、hemicalsby Differential Scanning CalorimetryE967 Test Method for Temperature Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-lyzersE968 Practice for Heat Flow Calibration of DifferentialScanning CalorimetersE1142 Terminology Relating to Thermophysical PropertiesE1231

9、Practice for Calculation of Hazard Potential Figuresof Merit for Thermally Unstable MaterialsE1860 Test Method for Elapsed Time Calibration of Ther-mal Analyzers2.2 Other Standard:NAS 1613 Seal Element, Packing, Preformed, EthylenePropylene Rubber33. Terminology3.1 Specific technical terms used in t

10、his standard are definedin Terminologies E473 and E1142.4. Summary of Test Method4.1 A small (milligram) quantity of the reactive material isheated at 10C/min through a temperature region where achemical reaction takes place. The exothermic heat flowproduced by the reaction is recorded as a function

11、 of tempera-ture and time by a differential scanning calorimeter. Integrationof the exothermic heat flow over time yields the heat ofreaction. If the heat flow is endothermic, then this test methodis not to be used.4.2 The test method can be used to determine the fraction ofa reaction that has occur

12、red in a partially reacted sample. The1This 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 April 1, 2018. Published May 2018. Originallyapproved in 2001.

13、Last previous edition approved in 2012 as E2160 04 (2012).DOI: 10.1520/E2160-04R18.2For 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 standards Document Summary pa

14、ge onthe ASTM website.3Available from National Aerospace Standard (NAS), Aerospace IndustriesAssociation (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209, http:/www.aia-aerospace.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United S

15、tatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to

16、Trade (TBT) Committee.1heat of reaction is determined for a specimen that is known tobe 100 % unreacted and is compared to the heat of reactiondetermined for the partially reacted sample. Appropriate cal-culation yields the fraction of the latter sample that wasunreacted.4.3 Subtracting the reaction

17、 fraction remaining from unity(1) yields the fraction reacted. The fraction reacted may beexpressed as percent. If the sample tested is a thermoset resin,the percent reacted is often called the percent of cure.4.4 The extrapolated onset temperature and peak heat flowtemperature are determined for th

18、e exothermic heat flowthermal curve from 4.1.5. Significance and Use5.1 This test method is useful in determining the extrapo-lated onset temperature, the peak heat flow temperature and theheat of reaction of a material. Any onset temperature deter-mined by this test method is not valid for use as t

19、he soleinformation used for determination of storage or processingconditions.5.2 This test method is useful in determining the fraction ofa reaction that has been completed in a sample prior to testing.This fraction of reaction that has been completed can be ameasure of the degree of cure of a therm

20、ally reactive polymeror can be a measure of decomposition of a thermally reactivematerial upon aging.5.3 The heat of reaction values may be used in PracticeE1231 to determine hazard potential figures-of-merit Explo-sion Potential and Shock Sensitivity.5.4 This test method may be used in research, pr

21、ocesscontrol, quality assurance, and specification acceptance.6. Apparatus6.1 Differential Scanning Calorimeter (DSC), capable ofmeasuring and recording heat flow as a function of temperatureand time. Such a DSC is composed of:6.1.1 Test Chamber, composed of:6.1.1.1 Furnace(s), to provide uniform co

22、ntrolled heating ofa specimen and reference to a constant temperature or at aconstant rate within the temperature range of 25 to 600C.6.1.1.2 Temperature Sensor, to provide an indication of thespecimen or furnace temperature to within 60.5C.6.1.1.3 Differential Sensor, to detect a heat flow differen

23、cebetween the specimen and reference equivalent to 0.2 mW.6.1.1.4 Means of Sustaining a Test Chamber Environment,of inert (for example, nitrogen, helium or argon) or reactive(for example, air) gas at a purge rate of 50 6 5 mL/min.NOTE 1Typically, at least 99 % pure nitrogen, helium or argon isemploy

24、ed when oxidation in air is a concern. Unless effects of moistureare to be studied, use of dry purge gas is recommended.6.1.1.5 Temperature Controller, capable of executing a spe-cific temperature program by operating the furnace(s) betweenselected temperature limits (ambient temperature to 600C) at

25、a heating rate between 2 and 20C/min constant to within60.1C/min.6.1.1.6 Recording Device, capable of recording and display-ing any portion (including signal noise) of the differential heatflow on the ordinate as a function of temperature or time on theabscissa.6.2 Containers, (pans, crucibles, vial

26、s, etc. and lids) that areinert to the specimen and reference materials and that are ofsuitable structural shape and integrity to contain the specimenand reference in accordance with the specific requirements ofthis test method.6.3 Balance, with a capacity of 100 mg or greater to weighspecimens and

27、containers, or both, to a sensitivity of 61 g.7. Safety Precautions7.1 The use of this test method for materials of unknownpotential hazards requires that precautions be taken during thesample preparation and testing.7.2 Where particle size reduction by grinding is necessary,the user of this test me

28、thod shall presume that the material ishazardous.7.3 Toxic or corrosive effluents, or both, may be releasedwhen heating the test specimen and could be harmful topersonnel or the apparatus. Use of an exhaust system to removesuch effluents is recommended.8. Calibration8.1 Perform any calibration proce

29、dures recommended bythe apparatus manufacturer as described in the OperationsManual.8.2 Calibrate the temperature signal to within 62C usingTest Method E967.8.3 Calibrate the heat flow signal to within 60.5 % usingPractice E968.8.4 Calibrate the elapsed time signal, or ascertain itsaccuracy, to with

30、in 60.5 % using Test Method E1860.9. Procedure9.1 Into a tared sample container, weigh to within 61g, 1to 2 mg of the test specimen. Record this mass as M in mg.Close the sample. Weigh the sealed container to within 61gand recorded this mass as N in mg.NOTE 2Because of the reactive nature of the mat

31、erials examined bythis test method, small specimen sizes shall be used unless the approxi-mate reactivity of the test specimen is known. Other specimen sizes maybe used but shall be reported. Make sure that the specimen is homogenousand represents the sample.NOTE 3Some substances may have non-reacti

32、ve components mixedwith the thermally reactive material. An example would be reinforcingfibers mixed with a thermally-curing polymer. A specification of thefraction of inert material in the mixture may accompany these materials.The user should be aware that such specifications involve tolerances sot

33、hat the actual fraction of inert material may vary within these tolerancesfrom lot to lot. In such cases, the actual fraction of inert material must betaken into account.NOTE 4For highly reactive materials, the selection of sample con-tainers can be particularly important. The material from which th

34、econtainer is constructed may catalyze the reaction or react with the samplematerial. Sealed containers may cause an autocatalytic effect or possiblya pressure effect. In open containers loss of material, and thereby loss ofE2160 04 (2018)2heat, could be an issue. Excessive pressurization of a sampl

35、e container canbe avoided by using vented containers, however, vented or unsealedcontainers may cause the measured heat of reaction to be much smallerthan the true value. See 12.4 for an example of such an effect.9.2 Heat the test specimen at a controlled rate of 10 60.1C/min from ambient until the

36、thermal curve returns tobaseline following the exothermic event. If the upper limit oftemperature for this test method, 600C, is reached before thethermal curve returns to baseline, then this test method is notapplicable.NOTE 5Other heating rates may be used but shall be reported.9.3 Cool the test s

37、pecimen to ambient temperature uponcompletion of the experiment.9.4 Reweigh the sample container. Compare this mass of thesealed sample container weight with N determined in 9.1.Report any specimen weight loss observed.9.5 Construct a line connecting the baseline before theexothermic reaction to tha

38、t after the reaction (see Fig. 1).NOTE 6For highly energetic reactions, a significant change may occurin the baseline prior to and following the exothermic reaction, due to asignificant change in the heat capacity of the reacted material in thesample container. Such an instance might be handled by t

39、he constructionof a baseline that is not a straight line. If a nonlinear baseline (for example,a sigmoidal baseline) is used it should be stated in the report and anexample of the constructed baseline and the thermal curve should beincluded also.9.6 Integrate the area, as a function of time, bounded

40、 by thethermal curve and the baseline constructed in 9.5. Record thisarea as the heat of the reaction (A)inmJ.NOTE 7The area bounded by the thermal curve and the constructedbaseline gives the heat of the reaction. Instrument software is most oftenused to integrate this area. Although such software p

41、ackages displaythermal curves as in Fig. 1, they calculate the bound area on a basis oftime. If older instruments without these software packages are used, or ifmanual checks are performed on newer instruments, then the manualintegration must be performed with the abscissa presented as a time(second

42、s) coordinate.NOTE 8The amount of material should be chosen such that themaximum heat flow is less than 8 mW. This requirement reduces thepotential of obtaining adiabatic heating of the sample.Adiabatic heating ofthe sample results in “leaning” peaks, an example of which is shown inFig. 2 (adapted f

43、rom Figure 11 of Jones (1996).4. For highly energeticmaterials, it might be impossible to satisfy simultaneously the direction of9.1 (using 1 to 2 mg of the test specimen) and the condition of this note(maximum heat flow less than 8 mW). If heat flow is larger than 8 mW andthe peak is not “leaning”,

44、 it should not be necessary to reduce samplemass. Or, in other words, when both directions cannot be metsimultaneously, sample mass need be reduced only if the observe peakleans.9.7 Construct a tangent to the leading edge of the exother-mic peak at the point of maximum rate of change andextrapolate

45、that tangent to the baseline constructed in 9.5.Record the intersection of the tangent with the baseline as theonset temperature (To).NOTE 9In some cases, reactions may have induction periods or othereffects that are manifested as exothermic deviations from the establishedbaseline well before the on

46、set temperature obtained by 9.7. Because of theimportance of these effects for highly reactive materials, an additionalonset temperature, the temperature of first deviation (Tf), is to be reportedalso. The temperature of first deviation is the temperature for which thethermal curve first deviates fr

47、om the established baseline. The temperatureof first deviation is to be noted in the report.NOTE 10Peak temperatures from two different determinations arecomparable only if the same conditions were used for both measurements,for example, sample mass and vent diameter.9.8 Record the temperature at th

48、e maximum deflection fromthe baseline constructed in 9.5 as the peak temperature (Tp).4Jones, D.E.G., and Augsten R.A., “Evaluation of Systems for Use in DSCMeasurements on Energetic Materials,” Thermochimica Acta, Vol 286, 1996, pp.355373.FIG. 1 Thermal Curve, Determination of Reported ValuesE2160

49、04 (2018)310. Calculations10.1 The normalized heat of reaction is calculated bydividing the heat of reaction (A) from 9.6 by the specimen mass(M) from 9.1:H 5 A/M10.2 Performing this test on a test specimen that is com-pletely unreacted, produces, by 10.1, the total heat of reactionfor this sample (Ht).10.3 The fraction of sample reacted is calculated by:fraction reacted 5 Ht 2 H! 100%/Ht 5 1 2 H/Ht! 100%10.3.1 For a thermoset resin, the Degree of Cure (DC) is thefraction reacted:DC 5 fraction reacted 5 Ht 2 H! 100%/Ht 5 1 2 H/Ht! 100%11. Report11.1 R