1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 16014-2:2012Plastics Determination ofaverage molecular mass andmolecular mass distribution ofpolymers using size-exclusionchromatographyPart 2: Universal calibration metho
2、dBS ISO 16014-2:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 16014-2:2012.It supersedes BS ISO 16014-2:2003 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/21, Testing of plastics.A list of organization
3、s 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 2012. Published by BSI StandardsLimited 2012ISBN 978
4、0 580 65172 4ICS 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 31 July 2012.Amendments issued since publicationDate Text affectedBS ISO 16014-2:2012 ISO
5、 2012Plastics Determination of average molecular mass and molecular mass distribution of polymers using size-exclusion chromatography Part 2: Universal calibration methodPlastiques Dtermination de la masse molculaire moyenne et de la distribution des masses molculaires des polymres par chromatograph
6、ie dexclusion strique Partie 2: Mthode dtalonnage universelleINTERNATIONAL STANDARDISO16014-2Second edition2012-07-01Reference numberISO 16014-2:2012(E)BS ISO 16014-2:2012ISO 16014-2:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise spec
7、ified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCas
8、e postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 16014-2:2012ISO 16014-2:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Terms and definitions . 24 Princi
9、ple of universal calibration method . 25 Reagents 36 Apparatus 37 Procedure 38 Data acquisition and processing 39 Expression of results . 49.1 Preparation of universal calibration curve . 49.2 Calculation of average molecular mass 49.3 Differential molecular mass distribution curve . 69.4 Cumulative
10、 molecular mass distribution curve 610 Precision 611 Test report . 711.1 General . 711.2 Apparatus and measurement parameters 711.3 Calibration of the system 711.4 Results . 7Annex A (informative) Supplementary information . 8Annex B (informative) K and a in the Mark-Houwink-Sakurada equation 11Bibl
11、iography .12BS ISO 16014-2:2012ISO 16014-2:2012(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 committees. Each
12、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 the International
13、 Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards ad
14、opted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of pat
15、ent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 16014-2 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-chemical properties.This second edition cancels and replaces the first edition (ISO 16014 2:2003). The main cha
16、nges are as follows:a) the scope has been editorially revised;b) the normative references have been updated.ISO 16014 consists of the following parts, under the general title Plastics Determination of average molecular mass and molecular mass distribution of polymers using size-exclusion chromatogra
17、phy: Part 1: General principles Part 2: Universal calibration method Part 3: Low-temperature method Part 4: High-temperature method Part 5: Method using light-scattering detectioniv ISO 2012 All rights reservedBS ISO 16014-2:2012INTERNATIONAL STANDARD ISO 16014-2:2012(E)Plastics Determination of ave
18、rage molecular mass and molecular mass distribution of polymers using size-exclusion chromatography Part 2: Universal calibration method1 ScopeThis part of ISO 16014 specifies a method for determining the average molecular mass and the molecular mass distribution of polymers using size-exclusion chr
19、omatography (SEC). The average molecular mass and the molecular mass distribution are calculated using a universal calibration curve instead of the conventional calibration curve.A list of documents related to this part of ISO 16014 is given in the Bibliography.NOTE The concept of the universal cali
20、bration method is based on a relationship by which the retention time in SEC depends on the size of the polymer molecule (the hydrodynamic volume) or on the product of the intrinsic viscosity and the molecular mass M. Many polymers classified as random-coil polymers (regardless of their chemical str
21、ucture, degree of branching, composition or tacticity) have been experimentally confirmed as following this relationship. The universal calibration curve is prepared by plotting the logarithm of M against the elution time t or elution volume V using polymer standards such as polystyrene with narrow
22、molecular mass distributions. The molecular mass Miof an unknown polymer sample can then be calculated from the value of M at each retention time using the universal calibration curve and or K and a in the Mark-Houwink-Sakurada equation ( = KMa M = KMa+1), where K is a constant and a is an exponent
23、depending on the experimental conditions. Therefore this test method is classified as a relative method as described in ISO 16014-1, but the average molecular masses and molecular mass distributions calculated by the method are equal to, or nearly equal to, the absolute values.2 Normative references
24、The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 472, Plastics VocabularyISO 16014-1:2012, Plas
25、tics Determination of average molecular mass and molecular mass distribution of polymers using size-exclusion chromatography Part 1: General principlesISO 16014-3:2012, Plastics Determination of average molecular mass and molecular mass distribution of polymers using size-exclusion chromatography Pa
26、rt 3: Low-temperature methodISO 16014-4:2012, Plastics Determination of average molecular mass and molecular mass distribution of polymers using size-exclusion chromatography Part 4: High-temperature method ISO 2012 All rights reserved 1BS ISO 16014-2:2012ISO 16014-2:2012(E)3 Terms and definitionsFo
27、r the purposes of this document, the terms and definitions given in ISO 472 and in ISO 16014-1 apply. The definitions of the various types of average molecular mass are reproduced here for convenience.Four types of average molecular mass are defined by the following equations, where Niis the number
28、of molecules of species i of molecular mass Miand a is the exponent of the Mark-Houwink-Sakurada equation.NOTE Although the definitions are the same as in ISO 16014-1, the values of Miin the equations are calculated by using a universal calibration curve as described in Clause 4.3.1number-average mo
29、lecular massMnMNMNiiiiin=()11(1)3.2mass-average molecular massMwMNMNMiiiiiiw=()()211(2)3.3z-average molecular massMzMNMNMiiiiiiz=()()3121(3)3.4viscosity-average molecular massMvMNMNMiiaiiiiav=+=()()/1111(4)4 Principle of universal calibration methodIn this part of ISO 16014, the experimental SEC pro
30、cedures are the same as in ISO 16014-1, ISO 16014-3 and ISO 16014-4, but the molecular mass Miat each elution time is calculated based on the universal calibration method. According to the theory, this method provides values for the average molecular mass and the molecular mass distribution that are
31、 equal to, or nearly equal to, the absolute values.2 ISO 2012 All rights reservedBS ISO 16014-2:2012ISO 16014-2:2012(E)According to theory, the size of a polymer in solution, the hydrodynamic volume Vh, is proportional to the product of the intrinsic viscosity and the molecular mass M as given by Eq
32、uation (5): /VM MVhh(5)In SEC, many random-coil polymers, regardless of their chemical structure, degree of branching, composition or tacticity, follow the same relationship, in which the retention time is proportional to the product of and M under the specific experimental conditions, including the
33、 column system, solvent and temperature. The relationship between the logarithm of M and the elution time is called the “universal calibration curve”, and the SEC technique for the determination of average molecular masses and molecular mass distributions using this calibration curve is called the “
34、universal calibration method”.As a first step, the universal calibration curve, retention time t versus the logarithm of M, is prepared using polymer standards with narrow molecular mass distributions and the Mark-Houwink-Sakurada equation:ssss= KMa(6)where the subscript “s” denotes “polymer standar
35、d”.Direct measurement of sis also possible.In the next step, the molecular mass Miat each retention time tiis calculated using the universal calibration curve and the Mark-Houwink-Sakurada equation for the polymer sample: = KMa(7) s, s,ii ii iaMMKM=+1(8)Again, direct measurement of is possible.Lastl
36、y, the average molecular mass and the molecular mass distribution are calculated from the molecular mass Miand peak height Hiat each retention time, using the equations given in 9.2, 9.3 and 9.4.For additional information on the universal calibration curve and the use of a conventional calibration c
37、urve based on universal calibration theory, see 9.1 and A.2.1.For additional information on the intrinsic viscosity , see A.2.2.The values of K and a in the Mark-Houwink-Sakurada equation for several polymers are given in Annex B.5 ReagentsSee ISO 16014-1:2012, Clause 5.6 ApparatusSee ISO 16014-1:20
38、12, Clause 6.7 ProcedureSee ISO 16014-1:2012, Clause 7.8 Data acquisition and processingSee ISO 16014-1:2012, Clause 8. ISO 2012 All rights reserved 3BS ISO 16014-2:2012ISO 16014-2:2012(E)9 Expression of results9.1 Preparation of universal calibration curveThe universal calibration curve is prepared
39、 by plotting the logarithm of sMsagainst the elution time for a number of polymer standards. The value of sfor each polymer standard may be calculated using the Mark-Houwink-Sakurada equation or measured directly under the specific elution conditions.For information on the molecular masses of commer
40、cially available polymer standards, see ISO 16014-1:2012, Annex B.For the expression of the universal calibration curve, polynomials containing terms up to t3are widely used. The addition of subsequent higher-power terms might improve the fit of the calibration curve.lg( )ssMAAt=+01(9)lg( )ssMAAt At
41、 At=+01 2233(10)wheresis the intrinsic viscosity of the polymer standard eluting at time t;Msis the molecular mass of the polymer standard eluting at time t;A0, A1, A2, A3are coefficients;t is the elution time.An example of a universal calibration curve is shown in Figure 1. Elution time can be repl
42、aced by elution volume Ve(Ve= t Q where Q is the flow rate).For the use of a conventional calibration curve based on universal calibration theory, see A.2.1 and Figure 2.9.2 Calculation of average molecular massCalculate the molecular mass Miof the polymer sample at elution time tiusing s,iMs,iat el
43、ution time tiand K and a in the Mark-Houwink-Sakurada equation or determined for the polymer sample from Equation (13). = KMa(polymer sample) (11) s, s,ii ii iaMMKM=+1(12)MMKMiiiaii i+( /)( )/( )s, s, s, s,11(13)Calculate the signal intensity Hiat each elution time tiusing the corrected test sample
44、chromatogram for which the baseline and the calculation range have been determined as specified in ISO 16014-1:2012, 8.3.1 and 8.3.2.4 ISO 2012 All rights reservedBS ISO 16014-2:2012ISO 16014-2:2012(E)Keyt elution time (min)Figure 1 Universal calibration curveKeyt elution time (min)lgM natural logar
45、ithm of the molecular massFigure 2 Conventional calibration curve for a polymer sample molecular mass M of polymer calculated from Equation (26) or (28)The average molecular mass and the polydispersity can be calculated from the values of Miand Hiusing Equations (14) to (18):MHHMiiniiinn=11(/)(14) I
46、SO 2012 All rights reserved 5BS ISO 16014-2:2012ISO 16014-2:2012(E)MHMHiiiniinw=()11(15)MHMHMiiiniiinz=()()211(16)MHMHiiainiinav=()/111(17)Polydispersity (in terms of Mwand Mn) = Mw/Mn(18)9.3 Differential molecular mass distribution curveThe differential molecular mass distribution curve is prepared
47、 by plotting dWi/d(lgMi) against lgMi. Wiis calculated from the following equations:WHHiiiin=1(19)wWIii=1(20)ddddWMwtMiiiii(lg) (lg)= (21)where I is the data acquisition interval, in minutes.If the sample contains components of molecular mass 1 000, draw a vertical boundary line at the point corresp
48、onding to M1 000.9.4 Cumulative molecular mass distribution curveThe cumulative molecular mass distribution curve is prepared by plotting the mass fraction Ciagainst lgMi,Cibeing calculated from the following equation:CWWijjji=+=()/112 (22)10 PrecisionAs the slope of the calibration curve for the sa
49、mple polymer is almost equal to that of the calibration curve for the polymer standards, the precision of this test method is expected to be almost the same as that given in Clause 10 of ISO 16014-3:2012 and ISO 16014-4:2012.6 ISO 2012 All rights reservedBS ISO 16014-2:2012ISO 16014-2:2012(E)11 Test report11.1
