BS ISO 11358-3-2013 Plastics Thermogravimetry (TG) of polymers Determination of the activation energy using the Ozawa-Friedman plot and analysis of the reaction kinetics《塑料 聚合物的热重分.pdf

1、BSI Standards PublicationBS ISO 11358-3:2013Plastics Thermogravimetry(TG) of polymersPart 3: Determination of the activationenergy using the Ozawa-Friedman plot andanalysis of the reaction kineticsCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not

2、for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 11358-3:2013.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/21, Testing of plasti

3、cs.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI Stand

4、ardsLimited 2014ISBN 978 0 580 69418 9ICS 83.080.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 28 February 2014.Amendments issued since publicationDate Text af

5、fectedCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013 ISO 2013Plastics Thermogravimetry (TG) of polymers Part 3: Determination of the activation e

6、nergy using the Ozawa-Friedman plot and analysis of the reaction kineticsPlastiques Thermogravimtrie (TG) des polymres Partie 3: Dtermination de lnergie dactivation laide du graphique dOzawa-Friedman et analyse cintique de la ractionINTERNATIONAL STANDARDISO11358-3First edition2013-12-15Reference nu

7、mberISO 11358-3:2013(E)Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013ISO 11358-3:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUME

8、NT ISO 2013All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can b

9、e requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandCopyright British Standards Institution P

10、rovided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013ISO 11358-3:2013(E) ISO 2013 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Terms and def

11、initions . 14 Principle 25 Apparatus . 26 Test specimens 27 Mass and temperature calibration 27.1 Mass calibration . 27.2 Temperature calibration . 38 Procedure. 38.1 General . 38.2 Non-oxidative reactions 48.3 Oxidative reactions 49 Expression of results 49.1 Graphical presentation . 49.2 Determina

12、tion of activation energy 59.3 Master curves . 610 Precision . 911 Test report . 9Annex A (informative) Mathematical background 10Bibliography .13Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted w

13、ithout license from IHS-,-,-BS ISO 11358-3:2013ISO 11358-3:2013(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical c

14、ommittees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with t

15、he International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for

16、the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.

17、 ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this d

18、ocument is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Tr

19、ade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 61, Plastics, Subcommittee SC 5, Physical-chemical properties.ISO 11358 consists of the following parts, under the general title Plastics Thermogravimetry (TG) of polymers: Part

20、 1: General principles Part 2: Determination of activation energy Part 3: Determination of the activation energy using the Ozawa-Friedman plot and the reaction kinetic analysisiv ISO 2013 All rights reservedCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled

21、 Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013ISO 11358-3:2013(E)IntroductionControlled rate thermogravimetry (CRTG) is used to study the decomposition of polymers. The Ozawa-Friedman method is typically applied to the analysis of data ob

22、tained by CRTG and also to that obtained by the combined use of isothermal thermogravimetry (isoTG) with conventional linear heating rate thermogravimetry (LHTG), i.e. using a constant heating rate. ISO 2013 All rights reserved vCopyright British Standards Institution Provided by IHS under license w

23、ith BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license f

24、rom IHS-,-,-BS ISO 11358-3:2013Plastics Thermogravimetry (TG) of polymers Part 3: Determination of the activation energy using the Ozawa-Friedman plot and analysis of the reaction kinetics1 ScopeThis International Standard specifies an analysis method for determining the activation energy using the

25、Ozawa-Friedman plot. It also specifies the preparation of master plots for verification of the reaction kinetics determined by thermogravimetry.The Ozawa-Friedman plot (logarithm of the rate of mass loss versus the reciprocal of absolute temperature at a given mass loss) is a derivative method that

26、can be applied to data obtained by any mode of temperature change in thermal analysis; e.g. isothermal, constant heating rate, sample-controlled thermal analysis, temperature jump, and repeated temperature scanning.2 Normative referencesThe following documents, in whole or in part, are normatively r

27、eferenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 11358-1, Plastics Thermogravimetry (TG) of polymers Part 1: General

28、 principlesISO 11358-2, Plastics Thermogravimetry (TG) of polymers Part 2: Determination of activation energy3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 11358-1, ISO 11358-2 and the following apply.3.1conversionCmmmm= ( )/( )ti fiwheremiis the ini

29、tial quantity, in mg;mtis the quantity at a particular time and temperature, in mg;mfis the final quantity, in mg.See ISO 11358-1 and ISO 11358-2.Note 1 to entry: It is also referred to as the mass loss fraction.INTERNATIONAL STANDARD ISO 11358-3:2013(E) ISO 2013 All rights reserved 1Copyright Briti

30、sh Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013ISO 11358-3:2013(E)3.2generalized timetgentERTdttgenaexp=0whereEais the activation energy, expressed in kJ/mol;R i

31、s the gas constant, expressed as 8.314 J/(mol K);T is the absolute temperature, expressed in Kelvin;t is time, expressed in minutes.3.3generalized rate of conversiondC/dtgendCdtERTdCdtgenaexp=3.4master curveplot that can be used to evaluate the results and investigate the reaction kinetics modelsNot

32、e 1 to entry: Examples of master curves are conversion versus the generalized time, conversion versus the generalized rate of conversion, generalized time versus the generalized rate of conversion.4 PrincipleTest specimens are heated using any temperature profile and the change in mass is measured a

33、s a function of temperature and time. At a given conversion, the logarithm of the rate of conversion is plotted versus the reciprocal of the absolute temperature, and the activation energy is calculated from the slope of the straight line fit to the data thus obtained.At least two of the master curv

34、es enable verification of the reaction kinetics analysis.5 ApparatusThe apparatus shall be in accordance with ISO 11358-1.6 Test specimensTest specimens shall be in the form of powder, pellets, flakes, filaments, or film. The test specimens shall be prepared by cutting the material, as necessary, to

35、 a size appropriate for the apparatus (see ISO 11358-1).7 Mass and temperature calibration7.1 Mass calibrationThe procedure of mass calibration is given in ISO 11358-1.2 ISO 2013 All rights reservedCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not

36、 for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013ISO 11358-3:2013(E)7.2 Temperature calibrationThe procedure of temperature calibration is given in ISO 11358-1.8 Procedure8.1 GeneralThe determination of the rate of conversion dC/dt is necessary for t

37、he analysis in this International Standard. The rate of conversion versus absolute temperature shall be determined.See ISO 11358-1 and ISO 11358-2.Perform tests using either an isothermal run, constant rate heating and cooling, sample mass controlled rate thermal analysis, temperature jump, repeated

38、 temperature scanning, or any combination of the above, using specimens of similar mass (1 %). For examples of linear heating rate thermogravimetry (LHTG) and sample mass controlled rate thermogravimetry (CRTG), see Figures 1a and 1b, respectively.KeyX t/minY1 (1 C)Y2 T/KFigure 1a Example of linear

39、heating rate thermogravimetry (LHTG) measurements of PMMA ISO 2013 All rights reserved 3Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 11358-3:2013ISO 11358-3

40、:2013(E)KeyX t/minY1 (1 C)Y2 T/KNOTE The units of %/min indicate the percentage weight loss per minute of the mass controlled rate.Figure 1b Example of sample mass controlled rate thermogravimetry (CRTG) measurements of PMMAPreferably, the specimen mass should be between 1 mg and 10 mg and the tempe

41、rature scanning rate between 2 K min1and 10 K min1.Determine the rate of conversion (or rate of change of mass loss fraction with time) at a given conversion (or given mass loss fraction).8.2 Non-oxidative reactionsThe procedure of non-oxidative reactions is given in ISO 11358-2.8.3 Oxidative reacti

42、onsThe procedure of oxidative reactions is given in ISO 11358-2.9 Expression of results9.1 Graphical presentationFor a given conversion (or mass loss fraction), present the thermogravimetry data in the form of a plot of the logarithm of the rate of conversion (or rate of change of mass loss fraction

43、 with time) versus the reciprocal of the absolute temperature, i.e. the Ozawa-Friedman plot, see Figure 2.4 ISO 2013 All rights reservedCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without lic

44、ense from IHS-,-,-BS ISO 11358-3:2013ISO 11358-3:2013(E)9.2 Determination of activation energyThe conversion (or the mass loss fraction) is not directly related to the quantity of reacted pieces, for example as in the random scission of the main chain of polymers. Generally, the rate formulae are as

45、 follows:Cf=() (1)andddtAERTg=()expa(2)where is the reacted fraction at time t;f() is an arbitrary function;A is the pre-exponential factor;g() is a function describing the reaction mechanism.By taking the logarithm of both sides of Formula (2) thenlnddtln AgERT=()a(3)When plotted for fixed values o

46、f , with various conversion rate values determined for different experimental temperature control profiles, the slope of the plot of lnddtversus 1Thas the value Ea/R and is used to determine the activation energy Ea, as the first term in the right side of Formula (3) is constant.As an example, the e

47、xperimental data presented in Figures 1a and 1b have been analysed, assuming an nthorder type reaction and thus C = f() = (Annex A), the results of which are presented in Table 1 and Figure 2.Table 1 The rate of conversion dC/dt and the estimated activation energy Eaat different conversion levels, d

48、etermined from the controlled rate thermogravimetry (CRTG) data presented in Figure 1b1000/T (K1)ln(dC/dt (% min1)at C = 0,21000/T (K1)ln(dC/dt (% min1)at C = 0,51000/T (K1)ln(dC/dt (% min1)at C = 0,8CRTG,0,09 %/min1,779 2,425 1,735 2,411 1,677 2,448CRTG,0,3 %/min1,731 1,161 1,693 1,183 1,641 1,288Activation Energy(kJmol1)Ozawa-Friedman plot 207,3 232,8 261,9 ISO 2013 All rights reserved 5Cop