1、Designation: E487 09E487 14Standard Test Method forConstant-Temperature Stability of Chemical Materials1This standard is issued under the fixed designation E487; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. 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 describes the assessment of constant-temperature stability (CTS) of chemical materials that undergoexothermic
3、reactions. The techniques and apparatus described may be used on solids, liquids, or slurries of chemical substances.1.2 When a series of materials is tested by this test method, the results permit ordering the materials relative to each other withrespect to their thermal stability.1.3 Limitations o
4、f Test:1.3.1 This test method is limited to ambient temperatures and above.1.3.2 This test method determines neither a safe storage temperature nor a safe processing temperature.NOTE 1A safe storage or processing temperature requires that any heat produced by a reaction be removed as fast as generat
5、ed and that properconsideration be given to hazards associated with reaction products.1.3.3 When this test method is used to order the relative thermal stability of materials, the tests must be run under the sameconfinement condition (see 8.3).1.4 The values stated in SI units are to be regarded as
6、standard. No other units of measurement are included in this standard.1.5 This standard should be used to measure and describe the properties of materials, products, or assemblies in response toheat and flame under controlled laboratory conditions and should not be used to describe or appraise the f
7、ire hazard or fire riskof materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a firerisk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particularend use.1.6 Thi
8、s standard may involve hazardous materials, operations, and equipment. This standard does not purport to address allof the safety problems associated with its use. It is the responsibility of whoever uses this standard to consult and establishappropriate safety and health practices and determine the
9、 applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and RheologyE537 Test Method for The Thermal Stability of Chemicals by Differential Scanning CalorimetryE967 Test Method for Temperature Calibration of Diffe
10、rential Scanning Calorimeters and Differential Thermal AnalyzersE968 Practice for Heat Flow Calibration of Differential Scanning CalorimetersE1445 Terminology Relating to Hazard Potential of ChemicalsE1860 Test Method for Elapsed Time Calibration of Thermal Analyzers3. Terminology3.1 Definitions:3.1
11、.1 constant-temperature stability (CTS) valuethe maximum temperature at which a chemical compound or mixture may beheld for a 2h120-min period under the conditions imposed in this test without exhibiting a measurable exothermic reaction.1 This test method is under the jurisdiction of ASTM Committee
12、E27 on Hazard Potential of Chemicals and is the direct responsibility of E27.02 on Thermal Stabilityand Condensed Phases.Current edition approved Oct. 1, 2009March 1, 2014. Published November 2009March 2014. Originally approved in 1974. Last previous edition approved in 20042009as E487 04.E487 09. D
13、OI: 10.1520/E0487-09. 10.1520/E0487-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not a
14、n ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate.
15、In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 The specialized terms in this standard are described in Terminolog
16、ies E473 and E1445 including differential scanningcalorimetry, differential thermal analysis, exotherm, and first -deviation-from-baseline.first-deviation-from-baseline.4. Summary of Test Method4.1 A sample of the chemical compound or mixture is placed in a glass or metal tube that is heated to a te
17、st temperature ofinterest. The sample temperature and heat flow or the difference between the sample temperature and the temperature of an inertreference material, are monitored over a 2-h120-min period or until an exothermic reaction is recorded. Test temperatures aredecreased in 10 C 10C intervals
18、 until no exothermic reaction is observed in the 2-h120-min test period. The ConstantTemperature Stability is determined and reported using either Method A or Method B.NOTE 2Test periods other than two 2 h120-min periods may be used but shall be reported.NOTE 3The processing times in many industrial
19、 scale unit operations (for example, drying, distillations, and the like) normally significantly exceedthe 2 h 120-min time period in this CTS test procedure. Therefore, for the effective application of the CTS data for industrial scale operations, the CTStime must be extended to be greater than the
20、 processing time in the actual operation.5. Significance and Use5.1 This test method is a useful adjunct to dynamic thermal tests that are performed under conditions in which the sampletemperature is increased continuously at a programmed rate. Results obtained under dynamic test conditions present
21、difficulties indetermining the temperature at which an exotherm initiates because onset temperature is dependent on heating rate. The testmethod described in the present standard attempts to determine the onset temperature under isothermal conditions where theheating rate is zero.6. Apparatus6.1 The
22、 design and complexity of the apparatus required for this 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 thermal analysisor differential scanning calorimetry equipment and techn
23、iques. Larger samples (up to 2 g) may be tested using a Kuhner MicroCTS apparatus.6.2 The following items are required to obtain the appropriate experimental data:6.2.1 A test chamber composed of:6.2.1.1 Furnace(s), to provide uniform controlled heating of a specimen and reference to a constant temp
24、erature.6.2.1.2 Temperature Sensor, to provide an indication of the specimen/furnace temperature to 60.1C.6.2.1.3 Differential Sensor, to detect a difference in heat flow or temperature between specimen and reference specimenequivalent to 1 mW or 40 mK.NOTE 4Sample temperature may be measured either
25、 absolutely or differentially. When differential temperature measurements are made, and areference material is used, the reference material should match the physical state and heat capacity of the sample as closely as practical. Typical referencematerials are calcined aluminum oxide, glass beads, si
26、licone oils, and a combination of these.NOTE 5Commercially available differential thermal analysis or differential scanning calorimetry apparatus capable of operating in an isothermal modemay be used. Alternatively, the apparatus may be assembled or fabricated from commercially available components
27、(see 12.1).6.2.2 A temperature Controller capable of heating from ambient to 400C at a rate of up1C/min to 50C/min and maintainingan isothermal temperature constant within that range to 61C for 120 min.6.2.3 AData Collection Device, to provide a means of acquiring, storing, and displaying measured o
28、r calculated signals, or both.The minimum output signals required for differential scanning calorimetry are heat flow, temperature and time.6.2.4 Containers (pans, crucibles, vials, test tubes, etc.) which are inert to the specimen and reference material and which areof suitable structure, shape, an
29、d integrity to contain the specimen and reference in accordance with the temperature and specimenmass requirements described in this section.6.3 A Balance with a capacity of 100 mg or more to weigh specimens and/or containers (pans, crucibles, vials, and the like)to 60.1 mg (see Note 6).7. Hazards7.
30、1 Dynamic thermal tests are normally carried out on small samples before the present test is undertaken. Therefore, theexperimenter should have some knowledge of the magnitude of hazard associated with the material. Larger samples should be usedonly after due consideration is given to the potential
31、for hazardous reaction. Thermodynamic calculations also can be used todetermine the potential hazard.7.2 Special precautions should be taken to protect personnel and equipment when the apparatus in use requires the insertion ofsamples into a heated block or furnace. These should include adequate shi
32、elding and ventilation of equipment, and face and handprotection.8. Sampling8.1 Specimens should be representative of the material being studied and should be prepared to achieve good thermal contactbetween the sample and container.E487 1428.2 Specimen size depends upon the sensitivity of the availa
33、ble apparatus (see 12.1).NOTE 6Specimen size of 47 mg is typically used in thermal analysis apparatus. The Kuhner Micro CTS uses up to 2 g of sample. For test specimensize greater than 1 g, record mass to 60.1 g.8.3 Specimens may be run in an unconfined or in a sealed specimen container, depending u
34、pon which condition has the morerelevance for the end use of the data.8.4 In selecting the material of construction of the specimen container, consideration should be given to possible interaction withthe specimen.9. Calibration9.1 Apparatus temperature calibration shall be performed according to Pr
35、actice E967 at a heating rate of 1 C/min.1C/min.9.2 Apparatus heat flow calibration shall be performed according to Practice E968 for differential scanning calorimeters.Differential thermal and Kuhner Micro CTS apparatus shall be calibrated according to the manufacturers instructions.9.3 Apparatus e
36、lapsed time shall be calibrated according to Test Method E1860.10. Procedure10.1 Bring the sample holder of the apparatus to a temperature 10 C 10C below that approximated as the onset temperaturein a previous differential thermal analysis measurement. Maintain control at the set temperature at no m
37、ore than 61 C.61C.NOTE 7The onset temperature may be determined using Practice E537.10.2 Place the samples and containers in the heated sample holder at the control temperature. Note the starting time as the timeof sample insertion and begin a temperature record versus time immediately.NOTE 8If the
38、test apparatus allows the sample to be brought to the test temperature in less than 10 min with not more than 1C overshoot, then placethe sample and reference in the heating unit at ambient temperature.10.3 Maintain the sample temperature for 2 h120 min or until an exothermic reaction is observed. R
39、eaction is indicated by anexothermic heat flow, departure of the temperature trace from the set heater temperature or from the reference temperaturedepending on the type apparatus used. The reaction is exothermic if it results in a measurable increase in sample temperature.Record the isothermal test
40、 temperature and the time interval from the start of the experiment to occurrence of an exotherm asmeasured by the first-deviation-from baseline.NOTE 9Other test periods may be used but shall be reported.10.4 When an exothermic reaction is observed, decrease the experimental temperature by 10C, and
41、repeat the experiment witha new sample. Follow the procedure until no exothermic reaction is observed in a 2-h120-min period.10.5 Repeat 10.4 using a sample twice as large as that used in the initial determinations. If a significant change in time ortemperature is noted repeat by again doubling the
42、sample size.10.6 Arectilinear plot of temperature versus time using the values obtained in 10.4 and 10.5 is helpful in minimizing the numberof tests required and in predicting the limiting CTS value.11. Calculations11.1 Method A:11.1.1 Report the highest temperature at which the first-deviation-from
43、-baseline (taken to be the indication of a exothermicreaction) is observed at more than 120 min. Report this value as CTS (Method A) = yy C yyC at 120 min.NOTE 10The first-deviation-from-baseline is determined on a scale that permits the peak of the exotherm to be displayed.11.2 Method B:11.2.1 Crea
44、te a rectilinear plot of the temperature versus time for the first-deviation-from-baseline (taken to be the indicationof an exothermic reaction) using the values obtained in 10.4 and 10.5. Using this plot interpolate the time axis to 120 min anddetermine the corresponding temperature. Report this va
45、lue as CTS (Method B = xx C xxC at 120 min.12. Performance Criteria for Test Apparatus12.1 The apparatus used for this test is considered adequate if a CTS value of 120120C to 140 C 140C is obtained for4nitroso-N-phenylbenzeneamine (also known as 4nitrosodiphenylamine) or a value of 210210C to 230 C
46、 230C for3methyl-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 construction of sampler container,E487 14313.1.4 Test conditions including atmosphere and degree of confine
47、ment,13.1.5 Temperatures investigated,13.1.6 Whether an exothermic reaction took place at each temperature,13.1.7 Time interval before each exotherm, and13.1.8 The Constant Temperature Stability determined including Method, temperature and time. For example CTS (Method A)= 140C.14. Precision and Bia
48、s14.1 Precision:14.1.1 An interlaboratory test program was conducted in 2003 in which 13 laboratories, using 7 instrument models supplied by4 vendors examined the Constant Temperature Stability of 1-phenyl-1H-tetrazole-5-thiol, known to decomposed autocatalytical-lyautocatalytically.3.14.1.2 Within
49、laboratory variability may be described using the repeatability value (r) obtained by multiplying the repeatabilitystandard deviation by 2.8. The repeatability value estimates the 95 % confidence limits, That is, two results obtained in the samelaboratory, using the same apparatus by the same operator should be considered suspect (at the 95 % confidence level) if they differby more than the repeatability value r.14.1.3 For MethodA, within laboratory precision is defined by 10.4 of this test method requiring that the test specimen be
