ASTM E2781-2016 Standard Practice for Evaluation of Methods for Determination of Kinetic Parameters by Calorimetry and Differential Scanning Calorimetry《用量热法和差示扫描量热法测定动力学参数的方法的评定标准.pdf
《ASTM E2781-2016 Standard Practice for Evaluation of Methods for Determination of Kinetic Parameters by Calorimetry and Differential Scanning Calorimetry《用量热法和差示扫描量热法测定动力学参数的方法的评定标准.pdf》由会员分享,可在线阅读,更多相关《ASTM E2781-2016 Standard Practice for Evaluation of Methods for Determination of Kinetic Parameters by Calorimetry and Differential Scanning Calorimetry《用量热法和差示扫描量热法测定动力学参数的方法的评定标准.pdf(7页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: E2781 11E2781 16Standard Practice forEvaluation of Methods for Determination of KineticParameters by Thermal AnalysisCalorimetry and DifferentialScanning Calorimetry1This standard is issued under the fixed designation E2781; the number immediately following the designation indicates the
2、 year oforiginal adoption or, in the case of 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. Scope Scope*1.1 It is the purpose of this practice to provid
3、e kinetic parameters for reference materials used for evaluation of thermal analysismethods, apparatus, and software where enthalpy and temperature are measured. This practice addresses both exothermic andendothermic, nth order, and autocatalytic reactions.1.2 The values stated in SI units are to be
4、 regarded as standard. No other units of measurement are included in this standard.1.3 There is no International Organization for Standardization (ISO) equivalent to this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the res
5、ponsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and RheologyE698 Test Method for Kinetic Paramet
6、ers for Thermally Unstable Materials Using Differential Scanning Calorimetry and theFlynn/Wall/Ozawa MethodE1142 Terminology Relating to Thermophysical PropertiesE1641 Test Method for Decomposition Kinetics by Thermogravimetry Using the Ozawa/Flynn/Wall MethodE1981 Guide for Assessing Thermal Stabil
7、ity of Materials by Methods of Accelerating Rate CalorimetryE2041 Test Method for Estimating Kinetic Parameters by Differential Scanning Calorimeter Using the Borchardt and DanielsMethodE2070 Test Method for Kinetic Parameters by Differential Scanning Calorimetry Using Isothermal Methods3. Terminolo
8、gy3.1 DefinitionsSpecific technical terms used in this practice are defined in Terminologies E473 and E1142, includingdifferential scanning calorimetry.4. Summary of Practice4.1 Kinetics is the study of the relationship of the extent of a chemical reaction to the independent parameters of time andte
9、mperature. This relationship is often described using the Arrhenius expression where:d/dt5Z f!exp2E/RT! (1)where: = fraction left to react,f() = some function of (),1 This practice is under the jurisdiction ofASTM Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee
10、 E37.02 on Standard ReferenceMaterials.Current edition approved March 1, 2011Nov. 1, 2016. Published April 2011November 2016. Originally approved in 2011. Last previous edition approved in 2011 as E2781 11. DOI: 10.1520/E2781-11.10.1520/E2781-16.2 For referencedASTM standards, visit theASTM website,
11、 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 an ASTM standard and is intended only to provide the user of an ASTM standard an indication of
12、 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. In all cases only the current versionof the standard as published by ASTM is to be considered
13、 the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E = activation energy (J/mol),R = gas constant (=8.314 J mol1 K1),T = absolute temperature (K), an
14、dZ = pre-exponential factor (1/sec).4.2 For many reactions of interest the description of the function of amount left to react is of the form:f!5m 12!n (2)where m and n are the overall reaction orders. This form of the concentration dependence is known as the auto-catalytic formor the Sestak-Berggre
15、n reaction reaction.(1).3 If the value of m equals 0, then f() reduces to the form of f() = (1 )n commonlycallcalled nth order reaction.4.3 Eq 1 may be evaluated in either its exponential or logarithmic form:lnd/dt! 5lnZ1lnf!2E/RT (3)4.4 The study of kinetics involves the determination of values of
16、E,Z,m, and n for a given reaction.NOTE 1Activation energy and pre-exponential factor are not independent parameters but are inter-related.NOTE 2The descriptions provided in Eq 1-3 are only mathematical models. That is, they represent the fitting of mathematical equations to often“noisy” experimental
17、 data. In practice, no such model will faithfully describe the complete reaction(s) under all conditions for the materials describedin this practice.4.5 Values for the kinetic parameter are typically in the ranges indicated below:log Z: 8 to 30 with Z in s 1E: 50 to 250 kJ/moln: 0.0 to 2.0m: 0 to 2.
18、0m: 0.0 to 2.04.6 By their nature, thermally reactive materials may change with time. For this reason, certified reference materials are notavailable for use in the evaluation of kinetic parameters. The user of this standardpractice may synthesize or purchase from acommercial laboratory supply house
19、 materials of suitable purity for use in this standard.practice.NOTE 3Storage of reference materials in a refrigerator may prolong shelf life. Observe manufacturersmanufacturers recommendations.4.7 The recommended values for the thermal activethermally reactive materials identified in this standardp
20、ractice are taken from“best values” found in the open literature as described in the accompanyingResearch Report RR:E37-1029tables45. Significance and Use5.1 The kinetic parameters provided in this standardpractice may be used to evaluate the performance of a standard, apparatus,techniques, or softw
21、are for the determination parameters (such as Test Methods E698, E1641, E2041, or E2070) using thermalanalysis techniques such as differential scanning calorimetry, and accelerating rate calorimetry (Guide E1981).The results obtainedby these approaches may be compared to the values provided by this
22、practice.NOTE 4Not all reference materials are suitable for each measurement technique.6. Hazards6.1 Thermally reactive materials evolve heat as part of the indicated reaction. Build up of this heat may lead to a dangerousover-pressure condition or to a self accelerating reaction. Operators shall us
23、e caution when working with such materials. Operatorsshall use as small amount of material as is practical for the measurement.6.2 The reference materials described in this standardpractice and their decomposition products may be explosive, carcinogenic,hazardous, toxic, or corrosive. Handling of th
24、ese materials should be performed by trained workers who are knowledgeable withthe Material Safety Data Sheets (MSDS)(SDS) for each material. Tetramethyl succinonitrile (TMSN), a decomposition product ofazobisisobutyronitrile (AIBN), is considered a very toxic (neurotoxic agent) and hazardous substa
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