1、Designation: E 2160 04Standard Test Method forHeat of Reaction of Thermally Reactive Materials byDifferential Scanning Calorimetry1This standard is issued under the fixed designation E 2160; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method determines the exothermic heat ofreaction of thermally reactive chemicals or che
3、mical 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 exothermicreaction.1.3 Th
4、is test method may be performed on solids, liquids orslurries.1.4 The applicable temperature range of this method is 25 to600C.1.5 SI units are to be regarded as the standard.1.6 There is no ISO method equivalent to this standard.1.7 This standard is related to Test Method E 537 and toNAS 1613, but
5、provides additional information.1.8 This standard may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and
6、 health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 473 Terminology Relating to Thermal AnalysisE 537 Test Method for Assessing the Thermal Stability ofChemicals by Methods of Thermal AnalysisE 967 Practice for Temper
7、ature Calibration of DifferentialScanning Calorimeters and Differential Thermal AnalyzersE 968 Practice of Heat Flow Calibration of DifferentialScanning CalorimetersE 1142 Terminology Relating to Thermophysical PropertiesE 1231 Practice for Hazard Potential Figures-of-Merit forThermally Unstable Mat
8、erialsE 1860 Test Method for Elapsed Time Calibration of Ther-mal Analyzers2.2 Other Standard:NAS 1613 Seal Element, Packing, Preformed, EthylenePropylene Rubber, National Aerospace Standard, Aero-space Industries Association of America, 1725 DeSalesSt., NM, Washington, DC 200363. Terminology3.1 Spe
9、cific technical terms used in this standard are definedin Terminologies E 473 and E 1142.4. 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 r
10、eaction 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 flow is endothermic, then this test methodis not to be used.4.2 The test method can be used to determine the fra
11、ction 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 reactiondetermined for the partially reacted sample. Appropriate cal-culation yields the fraction of the latter sampl
12、e 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 thermoset resin,the percent reacted is often called the percent of cure.4.4 The extrapolated onset temperature and
13、 peak heat flowtemperature are determined for the exothermic heat flowthermal curve from 4.1.1This test method is under the jurisdiction of ASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on ThermalAnalysis Test Methods.Current edition approved May 1
14、 2004. Published June 2004 Originally approvedin 2001. Last previous edition approved in 2001 as E 2160012For 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 This method is useful in determining the extrapolatedonset temperature, the peak heat flow temperature and the he
16、atof reaction of a material. Any onset temperature determined bythis method is not valid for use as the sole information used fordetermination of storage or processing conditions.5.2 This test method is useful in determining the fraction ofa reaction that has been completed in a sample prior to test
17、ing.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 decomposition of a thermally reactivematerial upon aging.5.3 The heat of reaction values may be used in PracticeE 1231 to determine hazard potential figur
18、es-of-merit Explo-sion Potential and Shock Sensitivity.5.4 This test method may be used in research, processcontrol, quality assurance, and specification acceptance.6. Apparatus6.1 Differential Scanning Calorimeter (DSC), capable ofmeasuring and recording heat flow as a function of temperatureand ti
19、me. 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 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 thespec
20、imen or furnace temperature to within 6 0.5C.6.1.1.3 Differential Sensor, to detect a heat flow differencebetween 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
21、 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 moistureare to be studied, use of dry purge gas is recommended.6.1.1.5 Temperature Controller, capable of executing aspecific temperature p
22、rogram by operating the furnace(s)between selected temperature limits (ambient temperature to600C) at a heating rate between 2 and 20C/min constant towithin 6 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
23、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 reference materials and that are ofsuitable structural shape and integrity to contain the specimenand reference in accordance with the specific r
24、equirements ofthis method.6.3 Balance, with a capacity of 100 mg or greater to weighspecimens and containers, or both, to a sensitivity of 6 1 g.7. Safety Precautions7.1 The use of this test method for materials of unknownpotential hazards requires that precautions be taken during thesample preparat
25、ion 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 corrosive effluents, or both, may be releasedwhen heating the test specimen and could be harmful topersonnel or the apparatus. Use of an ex
26、haust system to removesuch effluents is recommended.8. Calibration8.1 Perform any calibration procedures recommended bythe apparatus manufacturer as described in the OperationsManual.8.2 Calibrate the temperature signal to within 6 2 C usingPractice E 967.8.3 Calibrate the heat flow signal to within
27、 6 0.5 % usingPractice E 968.8.4 Calibrate the elapsed time signal, or ascertain its accu-racy, to within 6 0.5 % using Test Method E 1860.9. Procedure9.1 Into a tared sample container, weigh to within 6 1g, 1to 2 mg of the test specimen. Record this mass as M in mg.Close the sample. Weigh the seale
28、d container to within 6 1gand recorded this mass as N in mg.NOTE 2Because of the reactive nature of the materials examined bythis method, small specimen sizes shall be used unless the approximatereactivity of the test specimen is known. Other specimen sizes may beused but shall be reported. Make sur
29、e that the specimen is homogenousand represents the sample.NOTE 3Some substances may have non-reactive 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 ma
30、y accompany these materials.The user should be aware that such specifications involve tolerances sothat 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 mate
31、rials, 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 samplematerial. Sealed containers may cause an autocatalytic effect or possiblya pressure effect. In open containers loss of mater
32、ial, and thereby loss ofheat, could be an issue. Excessive pressurization of a sample 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
33、 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 oftemperature for this method, 600C, is reached before thethermal curve returns to baseline, then this method is notapplicable.NOTE
34、5Other heating rates may be used but shall be reported.9.3 Cool the test specimen 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 Con
35、struct a line connecting the baseline before theexothermic reaction to that after the reaction (see Fig. 1).E2160042NOTE 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 t
36、he 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 (e.g. asigmoidal baseline) is used it should be stated in the report and an exampleof the constructed baseline and the thermal curve sho
37、uld be included 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 heat of the reaction (A)inmJ.NOTE 7The area bounded by the thermal curve and the constructedbaseline gives the heat of the reaction. Instrument
38、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 basis oftime. If older instruments without these software packages are used, or ifmanual checks are performed on newer instruments, then the manua
39、lintegration must be performed with the abscissa presented as a time(seconds) 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
40、results in “leaning” peaks, an example of which is shown inFig. 2 (adapted from Figure 11 of Footnote 3).3. For highly energeticmaterials, it might be impossible to satisfy simultaneously the direction of3Jones, D. E. G., Augsten R. A., Evaluation of Systems for Use in DSCMeasurements on Energetic M
41、aterials, Thermochimica Acta, Vol 286, 1996, pp.355-373.FIG. 1 Thermal Curve, Determination of Reported ValuesFIG. 2 Example of a Leaning Thermal Curve Resulting From TooMuch Material in the Sample PanE21600439.1 (using 1 to 2 mg of the test specimen) and the condition of this note(maximum heat flow
42、 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 directions cannot be met simulta-neously, sample mass need be reduced only if the observe peak leans.9.7 Construct a tangent to the leading
43、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 tangent with the baseline as theonset temperature (To).NOTE 9In some cases, reactions may have induction periods or othereffects that are
44、manifested as exothermic deviations from the establishedbaseline well before the onset 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
45、 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 the report.NOTE 10Peak temperatures from two different determinations arecomparable only if the same conditions were used for both measu
46、rements,e.g., sample mass and vent diameter.9.8 Record the temperature at the maximum deflection fromthe baseline constructed in 9.5 as the peak temperature (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) fr
47、om 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 1H/Ht! 100 %10.3.1 For a thermoset resin, the Degree
48、 of Cure (DC)isthefraction reacted:DC 5 fraction reacted 5 Ht H! 100%/Ht 5 1H/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 manufacturer and modelnumber.11.1.3 The heating rate, temperature range, purge gas
49、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 determined in aninterlaboratory investigation. The interlaboratory study wasconduct
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