1、Designation: E2160 04 (Reapproved 2012)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 method is 25 to600C.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 equival
5、ent to this standard.1.7 This standard is related to Test Method E537 and toNAS 1613, but provides additional information.1.8 This standard may involve hazardous materials,operations, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse.
6、It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE537 Test Method for
7、 The Thermal Stability of Chemicalsby 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 Ther
8、mophysical PropertiesE1231 Practice for Calculation of Hazard Potential Figures-of-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 Rubber, National Aerospace Stan
9、dard, Aero-space Industries Association of America, 1725 DeSalesSt., NM, Washington, DC 200363. Terminology3.1 Specific technical terms used in this standard are definedin Terminologies E473 and E1142.4. Summary of Test Method4.1 A small (milligram) quantity of the reactive material isheated at 10C/
10、min through a temperature region where achemical reaction takes place. The exothermic heat flowproduced by the reaction is recorded as a function of tempera-ture and time by a differential scanning calorimeter. Integrationof the exothermic heat flow over time yields the heat ofreaction. If the heat
11、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 occurred in a partially reacted sample. Theheat of reaction is determined for a specimen that is known tobe 100 % unreacted and is compared to the heat of react
12、iondetermined for the partially reacted sample. Appropriate cal-culation yields the fraction of the latter sample that wasunreacted.4.3 Subtracting the reaction fraction remaining from unity(1) yields the fraction reacted. The fraction reacted may beexpressed as percent. If the sample tested is a th
13、ermoset resin,the percent reacted is often called the percent of cure.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 Sept. 1, 2012. Published Septem
14、ber 2012. Originallyapproved in 2001. Last previous edition approved in 2004 as E2160 04. DOI:10.1520/E2160-04R12.2For 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 th
15、e standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.4 The extrapolated onset temperature and peak heat flowtemperature are determined for the exothermic heat flowthermal curve from 4.
16、1.5. Significance and Use5.1 This method is useful in determining the extrapolatedonset temperature, the peak heat flow temperature and the heatof reaction of a material. Any onset temperature determined bythis method is not valid for use as the sole information used fordetermination of storage or p
17、rocessing conditions.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 thermally reactive polymeror can be a measure of decompositio
18、n 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, processcontrol, quality assurance, and specification accep
19、tance.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 controlled heating ofa specimen and reference to a constan
20、t 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 differencebetween the specimen and reference equivalent to 0.2 m
21、W.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 isemployed when oxidation in air is a concern. Unless effects of
22、 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) ata heating rate between 2 and 20C/min constant to within6
23、0.1C/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, vials, etc. and lids) that areinert to the specimen and refe
24、rence materials and that are ofsuitable structural shape and integrity to contain the specimenand reference in accordance with the specific requirements ofthis method.6.3 Balance, with a capacity of 100 mg or greater to weighspecimens and containers, or both, to a sensitivity of 61 g.7. Safety Preca
25、utions7.1 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 method shall presume that the material ishazardous.7.3 Toxic or
26、 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 procedures recommended bythe apparatus manufacturer as described i
27、n the OperationsManual.8.2 Calibrate the temperature signal to within 62C usingPractice 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 within 60.5 % using Test Method E1860.9. Procedure9.1 Into a tared s
28、ample 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 materials examined bythis method, small specimen sizes shall be use
29、d unless the approximatereactivity of the test specimen is known. Other specimen sizes may beused but shall be reported. Make sure that the specimen is homogenousand represents the sample.NOTE 3Some substances may have non-reactive components mixedwith the thermally reactive material. An example wou
30、ld 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 sothat the actual fraction of inert material may vary within these toleran
31、cesfrom 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 thecontainer is constructed may catalyze the reaction or react with the s
32、amplematerial. Sealed containers may cause an autocatalytic effect or possiblya pressure effect. In open containers loss of material, and thereby loss ofheat, could be an issue. Excessive pressurization of a sample container canbe avoided by using vented containers, however, vented or unsealedcontai
33、ners 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 thermal curve returns tobaseline following the exothermic event. If the upper limit oft
34、emperature for this method, 600C, is reached before thethermal curve returns to baseline, then this method is notapplicable.NOTE 5Other heating rates may be used but shall be reported.9.3 Cool the test specimen to ambient temperature uponcompletion of the experiment.E2160 04 (2012)29.4 Reweigh the s
35、ample 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 that after the reaction (see Fig. 1).NOTE 6For highly energetic reactions, a signifi
36、cant 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 the constructionof a baseline that is not a straight line. If a nonlinear baseline
37、 (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 by thethermal curve and the baseline constructed in 9.5. Record thisarea as the
38、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 packages displaythermal curves as in Fig. 1, they calculate the bound area on a ba
39、sis 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(seconds) coordinate.NOTE 8The amount of material should be chosen such that themaximum
40、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 from Figure 11 of Jones (1996).3. For highly energeticmaterials, it might be impos
41、sible 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”, it should not be necessary to reduce samplemass. Or, in other words, when both d
42、irections 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 that tangent to the baseline constructed in 9.5.Record the intersection of the ta
43、ngent 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 onset temperature obtained by 9.7. Because of theimportance of these effects for hi
44、ghly 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 from the established baseline. The temperatureof first deviation is to be noted in
45、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 the maximum deflection fromthe baseline constructed in 9.5 as the peak temperature
46、(Tp).10. 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).1
47、0.3 The fraction of sample reacted is calculated by:fraction reacted 5 Ht 2 H! 100%/Ht 5 1 2 H/Ht! 100%3Jones, 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 Repo
48、rted ValuesE2160 04 (2012)310.3.1 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 Report the following information:11.1.1 The identification of the sample characterized.11.1.2 The DSC apparatus by manufactur
49、er and modelnumber.11.1.3 The heating rate, temperature range, purge gas typeand rate and specimen container type and material used.11.1.4 The extrapolated onset temperature (To), the peaktemperature (Tp), the temperature of first deviation (Tf), andthe normalized heat of reaction (H).11.1.5 If appropriate or desired, report the fraction reactedor the degree of cure (DC) of the reaction.11.1.6 Any specimen weight loss observed.11.1.7 The specific dated version of this method used.12. Precision and Bias12.1 The precision of this test method was determin
