1、Designation: E 487 04Standard Test Method forConstant-Temperature Stability Of Chemical Materials1This standard is issued under the fixed designation E 487; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 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 describes the assessment of constant-temperature stability of chemical materials that undergo exo-thermic reaction
3、s. The techniques and apparatus described maybe used on solids, liquids, or slurries of chemical substances.1.2 When a series of materials is tested by this method, theresults permit ordering the materials relative to each other withrespect to their thermal stability.1.3 Limitations of Test:1.3.1 Th
4、is test method is limited to ambient temperaturesand above.1.3.2 This test method determines neither a safe storagetemperature nor a safe processing temperature.NOTE 1A safe storage or processing temperature requires that anyheat produced by a reaction be removed as fast as generated and thatproper
5、consideration be given to hazards associated with reaction prod-ucts.1.3.3 When this test method is used to order the relativethermal stability of materials, the tests must be run under thesame confinement condition (see 8.3).1.4 SI units are the standard.1.5 This standard should be used to measure
6、and describethe properties of materials, products, or assemblies in responseto heat and flame under controlled laboratory conditions andshould not be used to describe or appraise the fire hazard orfire risk of materials, products, or assemblies under actual fireconditions. However, results of this t
7、est may be used aselements of a fire risk assessment which takes into account allof the factors which are pertinent to an assessment of the firehazard of a particular end use.1.6 This standard may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all o
8、f the safety problems associated with its use. It isthe responsibility of whoever uses this standard to consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 473 Terminology Re
9、lating to Thermal AnalysisE 537 Test Method for Assessing the Thermal Stability ofChemicals by Methods of Thermal AnalysisE 967 Practice for Temperature Calibration of DifferentialScanning Calorimeters and Differential Thermal AnalyzersE 968 Practice for Heat Flow Calibration of DifferentialScanning
10、 CalorimetersE 1445 Terminology Relating to Hazardous Potential ofChemicalsE 1860 Test Method for Elapsed Time Calibration ofThermal Analyzers3. Terminology3.1 Definitions:3.2 constant-temperature stability (CTS) valuethe maxi-mum temperature at which a chemical compound or mixturemay be held for a
11、2h period under the conditions imposed inthis test without exhibiting a measurable exothermic reaction.3.3 The specialized terms in this standard are described inTerminologies E 473 and E1445.4. Summary of Test Method4.1 A sample of the chemical compound or mixture isplaced in a glass or metal tube
12、that is heated to a testtemperature of interest. The sample temperature and heat flowor the difference between the sample temperature and thetemperature of an inert reference material, are monitored overa 2-h period or until an exothermic reaction is recorded. Testtemperatures are decreased in 10 C
13、intervals until no exother-mic reaction is observed in the 2-h test period. The ConstantTemperature Stability is determined and reported using eitherMethod A or Method B.NOTE 2Test periods other than two 2 h may be used but shall bereportedNOTE 3The processing times in many industrial scale unit ope
14、rations(for example, drying, distillations, and the like) normally significantly1This test method is under the jurisdiction of ASTM Committee E27on HazardPotential of Chemicals and is the direct responsibility of E27.02 on ThermalStability and Condensed Phases.Current edition approved Oct. 1, 2004.
15、Published November 2004. Originallyapproved in 1974. Last previous edition approved in 1999 as E 487 - 99.2For 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
16、rds Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.exceed the 2 h time period in this CTS test procedure. Therefore, for theeffective application of the CTS data for industrial scale operatio
17、ns, theCTS time must be extended to be greater than the processing time in theactual operation.5. Significance and Use5.1 This test method is a useful adjunct to dynamic thermaltests that are performed under conditions in which the sampletemperature is increased continuously at a programmed rate.Res
18、ults obtained under dynamic test conditions present diffi-culties in determining the temperature at which an exotherminitiates because onset temperature is dependent on heatingrate. The test method described in the present standard attemptsto determine the onset temperature under isothermal conditio
19、nswhere the heating rate is zero.6. Apparatus6.1 The design and complexity of the apparatus required forthis method depends upon the size of the sample to be used. Ingeneral, observance of an exothermic reaction in small samples(less than 50 mg) is best done using differential thermalanalysis or dif
20、ferential scanning calorimetry equipment andtechniques. Larger samples (up to 2 g) may be tested using aKuhner Micro CTS apparatus.6.2 The following items are required to obtain the appro-priate experimental data:6.2.1 A test chamber composed of:6.2.1.1 Furnace(s), to provide uniform controlled heat
21、ing ofa specimen and reference to a constant temperature.6.2.1.2 Temperature Sensor, to provide an indication of thespecimen/furnace temperature to 6 0.1 C.6.2.1.3 Differential Sensor, to detect a difference in heatflow or temperature between specimen and reference specimenequivalent to 1 mW or 40 m
22、K.NOTE 4Sample temperature may be measured either absolutely ordifferentially. When differential temperature measurements are made, anda reference material is used, the reference material should match thephysical state and heat capacity of the sample as closely as practical.Typical reference materia
23、ls are calcined aluminum oxide, glass beads,silicone oils, and a combination of these.NOTE 5Commercially available differential thermal analysis or dif-ferential scanning calorimetry apparatus capable of operating in anisothermal mode may be used. Alternatively, the apparatus may beassembled or fabr
24、icated from commercially available components (see12.1).6.2.2 A temperature Controller capable of heating fromambient to 400 C at a rate of up to 50 C/min and maintainingan isothermal temperature constant within that range to 6 1Cfor 120 min.6.2.3 A Recording Device, to record and display differenti
25、alheat flow or differential temperature, test specimen temperatureand time to the sensitivities described above.6.2.4 Containers (pans, crucibles, vials, test tubes, etc.)which are inert to the specimen and reference material andwhich are of suitable structure, shape, and integrity to containthe spe
26、cimen and reference in accordance with the temperatureand specimen mass requirements described in this section.6.3 A Balance with a capacity of 100 mg or more to weighspecimens and/or containers (pans, crucibles, vials, and thelike) to 6 0.1 mg (see Note 6).7. Hazards7.1 Dynamic thermal tests are no
27、rmally carried out on smallsamples before the present test is undertaken. Therefore, theexperimenter should have some knowledge of the magnitude ofhazard associated with the material. Larger samples should beused only after due consideration is given to the potential forhazardous reaction. Thermodyn
28、amic calculations also can beused to determine the potential hazard.7.2 Special precautions should be taken to protect personneland equipment when the apparatus in use requires the insertionof samples into a heated block or furnace. These should includeadequate shielding and ventilation of equipment
29、, and face andhand protection.8. Sampling8.1 Specimens should be representative of the materialbeing studied and should be prepared to achieve good thermalcontact between the sample and container.8.2 Specimen size depends upon the sensitivity of theavailable apparatus (see 12.1).NOTE 6Specimen size
30、of 47 mg is typically used in thermal analysisapparatus. The Kuhner Micro CTS uses up to2gofsample. For testspecimen size greater than 1 g, record mass to 6 0.1 g.8.3 Specimens may be run in an unconfined or in a sealedspecimen container, depending upon which condition has themore relevance for the
31、end use of the data.8.4 In selecting the material of construction of the specimencontainer, consideration should be given to possible interactionwith the specimen.9. Calibration9.1 Apparatus temperature calibration shall be performedaccording to Practice E 967 at a heating rate of 1 C/min.9.2 Appara
32、tus heat flow calibration shall be performedaccording to Practice E 968 for differential scanning calorim-eters. Differential thermal and Kuhner Micro CTS apparatusshall be calibrated according to the manufacturers instruc-tions.9.3 Apparatus elapsed time shall be calibrated according toTest Method
33、E 1860.10. Procedure10.1 Bring the sample holder of the apparatus to a tempera-ture 10C below that approximated as the onset temperature ina previous differential thermal analysis measurement. Maintaincontrol at the set temperature at no more than 61 C.NOTE 7The onset temperature may be determined u
34、sing Practice E53710.2 Place the samples and containers in the heated sampleholder at the control temperature. Note the starting time as thetime of sample insertion and begin a temperature record versustime immediately.NOTE 8If the test apparatus allows the sample to be brought to the testtemperatur
35、e in less than 10 min with not more than 1 C overshoot, thenplace the sample and reference in the heating unit at ambient temperature10.3 Maintain the sample temperature for2horuntil anexothermic reaction is observed. Reaction is indicated by anE487042exothermic heat flow, departure of the temperatu
36、re trace fromthe set heater temperature or from the reference temperaturedepending on the type apparatus used. The reaction is exother-mic if it results in a measurable increase in sample temperature.Record the isothermal test temperature and the time intervalfrom the start of the experiment to occu
37、rrence of an exothermas measured by the first-deviation-from baseline.NOTE 9Other test periods may be used but shall be reported10.4 When an exothermic reaction is observed, decrease theexperimental temperature by 10 C, and repeat the experimentwith a new sample. Follow the procedure until no exothe
38、rmicreaction is observed in a 2-h period.10.5 Repeat 10.4 using a sample twice as large as that usedin the initial determinations. If a significant change in time ortemperature is noted repeat by again doubling the sample size.10.6 A rectilinear plot of temperature versus time using thevalues obtain
39、ed in 10.4 and 10.5 is helpful in minimizing thenumber of tests required and in predicting the limiting CTSvalue.11. Calculations11.1 Method A:11.1.1 Report the highest temperature at which the first-deviation-from -baseline (taken to be the indication of aexothermic reaction) is observed at more th
40、an 120 min. Reportthis value as CTS (Method A) = yy C at 120 min.11.2 Method B:11.2.1 Create a rectilinear plot of the temperature versustime for the first-deviation-from-baseline (taken to be theindication of an exothermic reaction) using the values obtainedin sections 10.4 and 10.5. Using this plo
41、t interpolate the timeaxis to 120 min and determine the corresponding temperature.Report this value as CTS (MethodB=xxCat120min.12. Performance Criteria for Test Apparatus12.1 The apparatus used for this test is considered adequateif a CTS value of 120 to 140 C is obtained for 4nitroso-N-phenylbenze
42、neamine (also known as 4nitrosodiphenylamine)or a value of 210 to 230 C for 3methyl-4nitrophenol.13. Report13.1 The report shall include the following:13.1.1 Description of the sample,13.1.2 Sample weight,13.1.3 Description of apparatus including materials or con-struction of sampler container,13.1.
43、4 Test conditions including atmosphere and degree ofconfinement,13.1.5 Temperatures investigated,13.1.6 Whether an exothermic reaction took place at eachtemperature,13.1.7 Time interval before each exotherm, and13.1.8 The Constant Temperature Stability determined in-cluding Method, temperature and t
44、ime. For example CTS(Method A) = 140 C.14. Precision and Bias14.1 Precision14.1.1 An interlaboratory test program was conducted in2003 in which 13 laboratories, using 7 instrument modelssupplied by 4 vendors examined the Constant TemperatureStability of 1-phenyl-1H-tetrazole-5-thiol, known to decom-
45、posed autocatalytically3.14.1.2 Within laboratory variability may be described usingthe repeatability value (r) obtained by multiplying the repeat-ability standard deviation by 2.8. The repeatability valueestimates the 95 % confidence limits, That is, two resultsobtained in the same laboratory, usin
46、g the same apparatus bythe same operator should be considered suspect (at the 95 %confidence level) if they differ by more than the repeatabilityvalue r.14.1.3 For method A, within laboratory precision is definedby section 10.4 of this standard requiring that the test specimenbe tested only at 10 C
47、intervals.14.1.4 For Method B, the within laboratory repeatabilitystandard deviation is 0.95 C.14.1.5 5 Between laboratory variability may be describedusing the reproducibility value (R) obtained by multiplying thereproducibility standard deviation by 2.8. The reproducibilityvalue estimates the 95 %
48、 confidence limits. That is, two resultsobtained in different laboratories, using different apparatus oroperators should be considered suspect (at the 95 % confidencelevel) if they differ by more than he reproducibility value R.14.1.6 6 For Method A, the between laboratory reproduc-ibility standard
49、deviation is 4.8 C.14.1.7 For Method B, the between laboratory reproducibil-ity standard deviation is 4.3 C.14.2 Bias14.2.1 Bias is the difference between the value obtained bythis standard and that of a reference material. There is noknown Constant Temperature Stability reference material norare CTS values known for phenyltetrazothiol, so bias may notbe evaluated.14.2.2 For Method A, the mean CTS value at 120 min forphenyltetrazolthiol was 103.3 C.14.2.3 For Method B, the mean CTS value at 120 min forphenyltetrazolthiol was 108.2 C.14.2.4 Phenyltet
