1、Designation: E2069 06 (Reapproved 2012)Standard Test Method forTemperature Calibration on Cooling of Differential ScanningCalorimeters1This standard is issued under the fixed designation E2069; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 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 temperature calibration ofdifferential scanning calorimeters on coo
3、ling using the differ-ence between transition temperatures upon heating and coolingin the temperature range of 50 to 185C. An offset in theindicated temperature between heating and coolingexperiments, within this temperature range, may be used toprovide temperature calibration on cooling at other te
4、mperatureranges.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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 t
5、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 6.2. Referenced Documents2.1 ASTM Standards:2D3418 Test Method for Transition Temperatures and En-thalpies of Fusion a
6、nd Crystallization of Polymers byDifferential Scanning CalorimetryE473 Terminology Relating to Thermal Analysis and Rhe-ologyE794 Test Method for MeltingAnd Crystallization Tempera-tures By Thermal AnalysisE928 Test Method for Purity by Differential Scanning Calo-rimetryE967 Test Method for Temperat
7、ure Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-lyzersE1970 Practice for Statistical Treatment of ThermoanalyticalData3. Terminology3.1 Specific technical terms used in this test method aredefined in Terminology E473.4. Summary of Test Method4.1 The temperature se
8、nsor of the DSC, used to determinethe temperature of a transition, is located close to but externalto the test specimen. This arrangement causes the indicatedtemperature to lead or lag the actual specimen temperature onheating/cooling causing the reported temperature to be higheron heating and lower
9、 on cooling than the actual specimentransition temperature. A DSC apparatus temperature, that hasbeen calibrated for heating experiments, needs to be re-calibrated for cooling experiments. Such a calibration oncooling is performed using a liquid crystal material, thetransition(s) for which are not s
10、ubject to super-heating orsuper-cooling.4.2 The transition temperature of a rapid, non-superheatingand non-supercooling transition is determined upon heatingand upon cooling. The difference between these two indicatedtemperatures provides an offset temperature value betweenheating and cooling experi
11、ments at the indicated rate. Thisoffset temperature value, when used with a precise temperaturecalibration upon heating, may serve as an instrument calibra-tion function upon cooling.5. Significance and Use5.1 This test method is useful in calibrating the temperaturesignal of a differential scanning
12、 calorimeter for cooling experi-ments such as the determination of crystallization temperaturesin Test Method D3418 and Test Method E794.5.2 This test method may be used for research,development, analytical, specification acceptance, quality as-surance and control purposes.6. Precautions6.1 Toxic or
13、 corrosive effluents, or both, may be releasedwhen heating the material of this test method and may beharmful to personnel and to the apparatus.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Calo-rime
14、try and Mass Loss.Current edition approved Sept. 1, 2012. Published September 2012. Originallyapproved in 2000. Last previous edition approved in 2006 as E2069 06. DOI:10.1520/E2069-06R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service
15、astm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. Apparatus7.1 Differential Scanning Calorimeter (DSC)The
16、essentialinstrumentation required providing the minimum differentialscanning calorimeter capability for this test method includes:7.1.1 A DSC Test Chamber, composed of:7.1.1.1 A Furnace(s), to provide uniform controlled heatingand cooling of a specimen and reference material to a constanttemperature
17、 or at a constant rate within the applicable tempera-ture range of this method.7.1.1.2 A Temperature Sensor, that indicates specimen orfurnace temperature to 60.01 C.7.1.1.3 A Differential Sensor, to detect a heat flow difference(DSC) between the specimen and reference with a range of atleast 100 mW
18、 readable to 61 W (DSC).7.1.1.4 A means of sustaining a purge gas rate of 10 to 1006 5 mL/min in the test chamber.NOTE 1Typically inert purge gases that inhibit specimen oxidation are99+ % pure nitrogen, argon or helium. Subambient operation requires drypurge gases. Dry gases are recommended for all
19、 experiments unless theeffect of moisture is part of the study.7.1.2 A Temperature Controller, capable of executing aspecific temperature program by operating the furnace orfurnaces between selected temperature limits at a rate oftemperature change of 10 C/min constant to within 60.1C/min or at an i
20、sothermal temperature constant to 60.1C.7.1.3 A Recording Device, capable of recording and display-ing fractions of the heat flow signal (DSC curve), including thesignal noise, on the Y-axis versus fractions of temperaturesignal, including the signal noise, on the X-axis.7.1.4 Containers, (pans, cru
21、cibles, vials, lids, closures,seals, etc.) that are inert to the specimen and referencematerials and that are of suitable structural shape and integrityto contain the specimen and reference in accordance with therequirements of this test method.NOTE 2DSC containers are commonly composed of aluminum
22、orother inert material of high thermal conductivity. Aluminum has beentested and found compatible with the materials used in this standard.7.1.5 Cooling Capability, at constant cooling rates of up to10C/min in the temperature range of 185 to 50C, to hastencool down from elevated temperatures, or to
23、sustain anisothermal subambient temperature, or both.7.2 A Balance, to weigh specimen and/or containers to 610g with a capacity of 100 mg or greater.8. Calibration Materials8.1 For the temperature range covered by manyapplications, the liquid crystal transitions of 99.8 to 99.9 %pure materials in Ta
24、ble 1 may be used for calibration. Thecalibrating liquid crystal materials3are known as M-24, BP-53and BCH-52.NOTE 3The purity of these liquid crystal materials may be determinedby Test Method E928 using the first liquid crystal transition prior to use(see Table 2).3The sole source of supply of thes
25、e materials known to the committee at thistime is EMD Chemicals Inc., 480 S. Democrat Road, Gibbstown, NJ 080271296.The part numbers for these chemicals are as follows: M-24 is pn 1.00008.9005,BP-53 is pn 1.00007.9005 and BCH-52 is pn 1.00006.9005. If you are aware ofalternative suppliers, please pr
26、ovide this information to ASTM headquarters. Yourcomments will receive careful consideration at a meeting of the responsibletechnical committee, which you may attend.TABLE 1 Transition Temperatures for Selected Liquid CrystalCalibration MaterialsLiquid CrystalMaterialATransition TypeBTransition Temp
27、erature,CKM-24 Cr SA327.5 54.5SA N 340.2 67.1BP-53 SA N 393.6 120.5BCH-52 N I 437.9 164.8AM-24 = 4-Cyano-4-octyloxybiphenylBP-53 = 4-(4-Pentyl-cyclohexyl)-benzoic acid-4-propyl-phenyl esterBCH-52 = 4-Ethyl-4-(4-propyl-cyclohexyl)-biphenylBCh = CholestericCr = CrystallineI = Isotropic liquidN = Nemat
28、icSA= Smectic ASC= Smectic CSC*= Chiral smectic CSI*= Smectic I*SJ*= Smectic J*CThe transition temperatures are dependent upon the purity of the liquid crystalmaterial. These transition temperatures are those for 99.9+ mol % pure materials.See Footnotes 5.TABLE 2 Temperatures of the Crystal to First
29、 Liquid Crystal Transition of the Calibrating MaterialsLiquid CrystalMaterialATransition TypeBTemperature,CEnthalpy Maximum TemperatureK C J/g CM-24 SA N 340.2 67.1 0.08 97BP-53 SA N 393.6 120.5 0.6 130BCH-52 N I 437.9 164.8 1.3 184AM-24 = 4-Cyano-4-octyloxybiphenylBP-53 = 4-(4-Pentyl-cyclohexyl)-be
30、nzoic acid-4-propyl-phenyl ester BCH-52 = 4-Ethyl-4-(4-propyl-cyclohexyl)-biphenylBCh = CholestericCr = CrystallineI = Isotropic liquidN = NematicSA= Smectic ASC= Smectic CSC*= Chiral smectic CSI*= Smectic I*SJ*= Smectic J*CThe transition temperatures are dependent upon the purity of the liquid crys
31、tal material. These transition temperatures are those for 99.9+ mol % pure materials. SeeFootnotes 5, 6, and 7.E2069 06 (2012)28.2 The approximate heat of transitions for these samples isshown in Table 2. The enthalpy of transition for M-24 is sosmall that it is detectable only on the most sensitive
32、 DSCinstrument.8.3 The actual specimen used for this test should be pre-melted in the crucible for the lowest variance.9. Calibration9.1 Perform any temperature calibration procedures recom-mended by the manufacturer of the differential scanningcalorimeter as described in the operations manual.9.2 P
33、erform the temperature calibration of the differentialscanning calorimeter using Practice E967 and the heating rateof 10C/min. Indium is recommended as at least one of thecalibration materials.NOTE 4For the purposes of this standard, temperature calibration onheating is performed at 10C/min and on c
34、ooling at 10C/min. Other ratesfor either heating or cooling may be used but shall be reported.10. Procedure10.1 Select a suitable calibrating liquid crystal materialfrom Table 1.10.2 Into a clean, tared specimen container weigh 3.0 to 5.0mg of the liquid crystal calibration material.NOTE 5Larger spe
35、cimen masses should not be used, as they will resultin increased thermal lag effects.10.3 Load the specimen into the test chamber, purge withdry nitrogen (or other inert purge gas) at the flow rate to beused for the subsequent application.10.4 Heat the specimen rapidly to the maximum tempera-ture fo
36、r the material shown in Table 2 and hold isothermally for1 min.NOTE 6The transition temperature to the isotropic phase dependsupon the calibration material selected and its purity.NOTE 7The samples are not stable above the maximum temperaturelisted in Table 2. Discard the specimen and make a new one
37、 if it has beenexposed to a temperature above the maximum temperature.10.5 Cool the specimen at 10C/min to 30C and holdisothermally for 1 min. Record the resultant thermal curveupon cooling (see Note 4).NOTE 8Liquid crystalline transitions are very narrow. Data collectionrates of one data point ever
38、y 0.05C (preferably every 0.01C) shall beused to achieve the precision required.10.6 Heat the specimen at 10 C/min to 30 C above thetemperature of the transition to the isotropic phase as indicatedin Table 1. Record the resulting thermal curve upon heating(see Note 4).10.7 From the resultant thermal
39、 curve upon cooling from10.5, determine the extrapolated onset temperature (Tc)to60.01C for each transition in Table 2 observed as illustratedin Fig. 1.NOTE 9Use only a transition where the signal returns to baselinebefore the transition onset.FIG. 1 Cooling Curve for M-24E2069 06 (2012)3NOTE 10Reta
40、in all available significant figures for these calculationsand round to the final result to the number of significant figures describedin section 1310.8 From the resultant thermal curve upon heating from10.6, determine the extrapolated onset temperature (Th)to60.01C for each transition in Table 2 ob
41、served as illustrated inFig. 2 (see Note 9).Fig. 3Fig. 4Fig. 5Fig. 610.9 Calculate the offset temperature (T) for each liquidcrystal transition to 60.01C according to 11.1.11. Calculation11.1 Calculate the offset temperature (T)to60.01C foreach transition according to Eq 1:T 5 Th2 Tc(1)where:Th= the
42、 transition temperature of a specific liquid crystaltransition observed on heating,Tc= the temperature of the same transition measured oncooling, andT = the offset temperature for the specific liquid crystaltransition.11.2 In an application cooling experiment, where the differ-ential scanning calori
43、meter has been calibrated upon heating,the temperature of a cooling transition within or without the 50to 185 C temperature range may be determined using Eq 2:Tx5 To1T (2)where:Tx= the temperature of the unknown transition uponcooling,To= the observed temperature upon cooling, andT = the offset temp
44、erature determined for the specificheating rate-cooling rate combination determined inthis test method.12. Report12.1 Report the following information:12.1.1 Description of the differential scanning calorimeterused for the test including model and serial number,12.1.2 Complete identification and des
45、cription of the refer-ence materials and their transitions used including source,method or purification (if any) and purity,12.1.3 Statement of the sample name and mass,12.1.4 Statement of the crucible material,12.1.5 Statement of the temperature program rate on heatingand cooling,12.1.6 Statement o
46、f the maximum temperature,12.1.7 Identification of the specimen atmosphere by purgegas composition, purity and flow rate,12.1.8 The value of the offset temperature (T) term, and12.1.9 The specific dated version of the ASTM standardused.FIG. 2 Heating Curve for M-24E2069 06 (2012)4FIG. 3 Cooling Curv
47、e for HP-53FIG. 4 Heating Curve for HP-53E2069 06 (2012)5FIG. 5 Cooling Curve for BCH-52FIG. 6 Heating Curve for BCH-52E2069 06 (2012)613. Precision and Bias13.1 An interlaboratory test is planned for to determine theprecision and bias of this test method. Anyone wishing toparticipate in this interl
48、aboratory test may contact the E37 StaffManager at ASTM Headquarters.13.2 Precision:13.2.1 Testing in the manufacturers laboratory indicatesthat the standard deviation for transition temperature is 60.4Cfor all three materials.13.3 Bias:13.3.1 Testing on DSCs from different manufacturers, in-dicates
49、 that the calibration (T) may differ for different heatingand cooling rates.14. Keywords14.1 calibration; cooling; differential scanning calorimetry;temperature; thermal analysisASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin 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 s
