1、Designation: E2046 14Standard Test Method forReaction Induction Time by Thermal Analysis1This standard is issued under the fixed designation E2046; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 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 measurement of ReactionInduction Time (RIT) of chemical materials that undergoexothermic reactions with an ind
3、uction period. The techniquesand apparatus described may be used for solids, liquids, orslurries of chemical substances. The temperature range coveredby this test method is typically from ambient to 400C. Thisrange may be extended depending upon the apparatus used.1.2 The RIT is a relative index val
4、ue, not an absolutethermodynamic property.As an index value, the RIT value maychange depending upon experimental conditions. A compari-son of RIT values may be made only for materials tested undersimilar conditions of apparatus, specimen size, and so forth.Furthermore, the RIT value may not predict
5、behavior of largequantities of material.1.3 The RIT shall not be used by itself to establish a safeoperating temperature. It may be used in conjunction withother test methods (for example, E487, E537, and E1981)aspart of a hazard analysis of a particular operation.1.4 This test method may be used fo
6、r RIT values greaterthan 15 min (as relative imprecision increases at shorterperiods).1.5 This test method is used to study catalytic, autocatalytic,and accelerating reactions. These reactions depend upon timeas well as temperature. Such reactions are often studied byfixing one experimental paramete
7、r (that is, time or tempera-ture) and then measuring the other parameter (that is, tempera-ture or time). This test method measures time to reaction onsetdetection under isothermal conditions. It is related to TestMethod E487 that measures detected reaction onset tempera-ture under constant time con
8、ditions1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 There is no ISO standard equivalent to this test method.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
9、is theresponsibility of the user of 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:2D3350 Specification for Polyethylene Plastics Pipe and Fit-tings Materi
10、alsD3895 Test Method for Oxidative-Induction Time of Poly-olefins by Differential Scanning CalorimetryD4565 Test Methods for Physical and Environmental Per-formance Properties of Insulations and Jackets for Tele-communications Wire and CableD5483 Test Method for Oxidation Induction Time of Lubri-cat
11、ing Greases by Pressure Differential Scanning Calorim-etryD6186 Test Method for Oxidation Induction Time of Lubri-cating Oils by Pressure Differential Scanning Calorimetry(PDSC)E473 Terminology Relating to Thermal Analysis and Rhe-ologyE487 Test Method for Constant-Temperature Stability ofChemical M
12、aterialsE537 Test Method for 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 CalorimetersE1445
13、Terminology Relating to Hazard Potential of Chemi-calsE1858 Test Method for Determining Oxidation InductionTime of Hydrocarbons by Differential Scanning Calorim-etryE1860 Test Method for Elapsed Time Calibration of Ther-mal Analyzers1This test method is under the jurisdiction of ASTM Committee E27 o
14、n HazardPotential of Chemicals and is the direct responsibility of Subcommittee E27.02 onThermal Stability and Condensed Phases.Current edition approved Jan. 1, 2014. Published February 2014. Originallyapproved in 1999. Last previous edition approved in 2008 as E2046 08. DOI:10.1520/E2046-14.2For re
15、ferenced 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 standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, We
16、st Conshohocken, PA 19428-2959. United States1E1981 Guide for Assessing Thermal Stability of Materialsby Methods of Accelerating Rate CalorimetryE2070 Test Method for Kinetic Parameters by DifferentialScanning Calorimetry Using Isothermal Methods3. Terminology3.1 The specialized terms used in this t
17、est method aredescribed in Terminologies E473 and E1445, including differ-ential scanning calorimetry, differential thermal analysis, ex-trapolated onset value, first-deviation-from-baseline, onsetvalue, isothermal, and reaction.3.2 Definitions of Terms Specific to This Standard:3.2.1 constant tempe
18、rature stability (CTS) value, nthemaximum temperature at which a chemical compound ormixture may be held for a minimum of two hours withoutexhibiting a measurable exothermic reaction. (See Test MethodE487.)3.2.2 reaction induction time (RIT) value, nthe time achemical compound or mixture may be held
19、 under isothermalconditions until it exhibits a specified exothermic reaction.4. Summary of Test Method4.1 A specimen of the chemical compound or mixture isplaced in an inert container that is then heated to an operator-selected test temperature of interest. The specimen temperatureand the differenc
20、e in heat flow or temperature between the testspecimen and an inert reference are monitored until an exo-thermic reaction is recorded. The time from the attainment ofthe isothermal test temperature until the extrapolated onset tothe exothermic reaction is taken as the Reaction InductionTime.4.2 Usin
21、g fresh specimens measurements at more than oneisothermal test temperature may be made.4.3 The RIT is expressed as time at a specific test tempera-ture. For example:RIT = 120 min at 100C5. Significance and Use5.1 This test method measures the time to extrapolated onsetof an exothermic reaction under
22、 constant temperature (isother-mal) conditions for reactions which have an induction period,for example, those which are catalytic, autocatalytic, or accel-erating in nature or which contain reaction inhibitors.5.2 The RIT determined by this test method is an indexmeasurement that is useful for comp
23、aring one material toanother at the test temperature of interest and in the sameapparatus type only.5.3 This test method is a useful adjunct to dynamic thermaltests, such as Test Method E537, which are performed underconditions in which the sample temperature is increasedcontinuously at constant rat
24、e. Results obtained under dynamictest conditions may result in higher estimates of temperature atwhich an exothermic reaction initiates because the detectedonset temperature is dependent upon the heating rate andbecause dynamic methods allow insufficient time for autocata-lytic reactions to measurab
25、ly affect the onset temperature.5.4 RIT values determined under a series of isothermal testconditions may be plotted as their logarithm versus thereciprocal of the absolute temperature to produce a plot, theslope of which is proportional to the activation energy of thereaction as described in Test M
26、ethod E2070.5.5 This test method may be used in research anddevelopment, manufacturing, process and quality control, andregulatory compliance.5.6 This test method is similar to that for Oxidation Induc-tion Time (OIT) (for example, Specification D3350 and TestMethods D3895, D4565, D5483, D6186, and
27、E1858) where thetime to the oxidation reaction under isothermal test conditionsis measured. The OIT test method measures the presence ofantioxidant packages and is a relative measurement of amaterials resistance to oxidation.6. Apparatus6.1 The design and complexity of the apparatus required forthis
28、 test method depends upon the size of the specimen to beused. In general, observation of an exothermic reaction in smallspecimens (less than 50 mg) is performed using differentialscanning calorimetry or differential thermal analysis equipmentand techniques. Large samples (up to 2 g) may be tested us
29、ingdevices such as the Kuhner Micro CTS apparatus.6.2 The following items are required to obtain the appro-priate experimental data.NOTE 1Commercially available differential scanning calorimetryapparatus may be used. Alternatively, the apparatus may be assembled orfabricated from commercially availa
30、ble components.6.2.1 Test Chamber, composed of the following:6.2.1.1 Furnace(s), to provide uniform controlled heating ofa specimen and reference to a constant temperature.6.2.1.2 Temperature Sensor, to provide an indication ofspecimen/furnace temperature to 60.1 K.6.2.1.3 Differential Sensor, to de
31、tect a difference in heat flow(or temperature) between the specimen and the referencespecimen equivalent to 10 W or 0.01 mK.NOTE 2A reference material is used when differential heat flow ordifferential temperature measurements are made. The reference materialshould match the physical state and heat
32、capacity of the specimen asclosely as practical. Typical reference materials include calcined alumi-num oxide, glass beads, silicone oil, or combinations thereof.6.2.1.4 Means of Sustaining a Test Chamber Environment,through the use of an air purge gas at a rate of 10 to 100 6 5mL/min.NOTE 3Typicall
33、y, air or inert 99.9+ % pure nitrogen, argon, or heliumis employed (when oxidation in air is a concern). Unless effects ofmoisture are to be studied, use of dry purge gas is recommended.NOTE 4For the Kuhner Micro CTS apparatus, the purge gas isprovided by operation in a laboratory hood with the door
34、(s) approximately50 % closed.6.2.2 Temperature Controller, capable of heating from am-bient to 400C at a rate of up to 20C/min and maintaining anisothermal temperature constant within that range of 60.4Cfor the duration of the test, or both.6.2.3 A Data Recording Device, to provide a means ofacquiri
35、ng, storing, and displaying measured or calculatedE2046 142signals, or both. The minimum output signals required fordifferential scanning calorimetry or differential thermal analy-sis are heatflow (or differential temperature), temperature, andtime.6.2.4 Containers (pans, crucibles, vials, test tube
36、s, and soforth, and lids), which are inert to the specimen and referencematerials at the maximum temperature used and which are ofsuitable structure, shape, and integrity to contain the specimenand reference in accordance with the temperature and massrequirements as described in this section.6.3 Bal
37、ance, with a capacity of 100 mg or more to weighspecimens or containers to 60.1 mg.NOTE 5A balance capacity of 10 g or more with a readability to 60.1g is required for use with the Kuhner Micro CTS device.7. Hazards7.1 Dynamic thermal tests, utilizing milligram quantities ofmaterials, such as Test M
38、ethod E537, are normally conductedon specimens before the present test is undertaken. Theexperimenter shall have sufficient knowledge of the magnitudeof hazard associated with the material. Larger specimens shallbe used only after due consideration is given to the potential forhazardous reaction. Th
39、ermodynamic calculations also may beused to determine the potential hazard.7.2 Special precautions shall be taken to protect personneland equipment when the apparatus in use requires the insertionof specimens into a heated block or furnace. These shallinclude adequate shielding and ventilation of eq
40、uipment, andface and hand protection (see Note 8).8. Sampling8.1 Specimens shall be representative of the material beingstudied and shall be prepared to achieve good thermal contactbetween the specimen and the container.8.2 Specimen size depends upon the sensitivity of theavailable apparatus.NOTE 6S
41、pecimen size of 1 to 7 mg is typically used in thermalanalysis apparatus. Specimen size of 1 to2gistypically used with theKuhner Micro CTS apparatus.8.3 Specimens may be run in an unconfined or in a sealedcontainer, depending upon which condition has the morerelevance for the end use of the data.9.
42、Calibration9.1 Apparatus temperature calibration shall be performed inaccordance with Practice E967 at a heating rate of 1C/min.9.2 Apparatus heat flow calibration may be performed inaccordance with Practice E968.9.3 Apparatus elapsed time shall be verified to be better than61 % by Test Method E1860
43、.10. Procedure10.1 Weigh 1 to 7 mg with a precision of 61 mg of the testspecimen into a clean specimen container. Seal the container, ifdesired.NOTE 7The Kuhner Micro CTS device uses up to 2-g specimens. Forspecimens of a size greater than 1 g, record mass to 60.1 g.10.2 Place the test specimen into
44、 the apparatus onto thesample position, at ambient temperature conditions. Place aspecimen container containing 1 to 7 mg of inert referencematerial (1 to 2 g for the Kuhner Micro CTS) in the referenceposition.10.3 Heat the test specimen and reference material fromambient to the isothermal temperatu
45、re of test at 20C/min withno more than 1C overshoot. Zero time is recorded when thespecimen test temperature reaches the isothermal test tempera-ture 61C. Record the thermal curve.NOTE 8In some apparatus, it may be possible to load the specimenand reference into the furnace preheated to the isotherm
46、al test tempera-ture. Appropriate provisions shall be made to ensure the safety of theoperator.NOTE 9A dynamic test method, such as Test Method E537 may beused to estimate potential isothermal test temperatures.10.4 Record the sample temperature 5 min into the experi-ment.10.5 Terminate the experime
47、nt when the peak of the reac-tion exotherm is observed or when no exotherm is observed orafter an operator-selected time. (In the absence of otherinformation, after 200 min). The reaction is exothermic if itresults in a measurable increase in specimen temperature orheat flow above baseline.10.6 Disp
48、lay the thermal curve with differential heat flow ordifferential temperature on the Y-axis and time on the X-axis.Extend the recorded baseline beyond the reaction exotherm.Construct a tangent at the point of the most rapid rate ofincrease in heat flow and extrapolate it to intersect with theconstruc
49、ted baseline. The time at the intersection of these twolines is the reaction induction time. (See Fig. 1.)NOTE 10The precision of this test method is a constant value (seeSection 12) and does not depend upon the measured value. For this reason,this test method is applicable to RIT values greater than 15 min. If RITvalues of less than 15 min are observed, the test temperature may belowered to obtain longer RIT values.NOTE 11In some cases, where agreed upon by the parties involved,the time at the first deviation from baseline may be taken as the RITvalues. This
