1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 14322:2012Plastics Epoxy resins Determination of degree ofcrosslinking of crosslinkedepoxy resins by differentialscanning calorimetryBS ISO 14322:2012 BRITISH STANDARDNati
2、onal forewordThis British Standard is the UK implementation of ISO 14322:2012. The UK participation in its preparation was entrusted to TechnicalCommittee PRI/42, Fibre reinforced thermosetting plastics and prepregs.A list of organizations represented on this committee can be obtained on request to
3、its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012ISBN 978 0 580 69421 9 ICS 83.080.10 Compliance with a British Stan
4、dard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 August 2012.Amendments issued since publicationDate T e x t a f f e c t e d ISO 2012Plastics Epoxy resins Determination of degree of crossli
5、nking of crosslinked epoxy resins by differential scanning calorimetryPlastiques Rsines poxydes Dtermination du degr de rticulation des rsines poxydes rticules par analyse calorimtrique diffrentielleINTERNATIONAL STANDARDISO 14322First edition 2012-06-15Reference number ISO 14322:2012(E)BS ISO 14322
6、:2012ISO 14322:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, 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 pe
7、rmission in writing 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 SwitzerlandBS ISO 14322:2012ISO 14322:2012(E
8、)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 member body interested in a subject for which a t
9、echnical 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 Electrotechnical Commission (IEC) on all matters
10、 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 adopted by the technical committees are circulated
11、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 patent rights. ISO shall not be held responsible for
12、 identifying any or all such patent rights.ISO 14322 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 12, Thermosetting materials. ISO 2012 All rights reserved iiiBS ISO 14322:2012ISO 14322:2012(E)IntroductionIt is possible to determine the degree of crosslinking of a crossli
13、nked epoxy resin by observing changes in its mechanical, electrical or thermal properties.However, such an approach is inadequate in cases in which the test sample is to be evaluated as is or is to be examined under various crosslinking conditions. This International Standard provides a method where
14、by the degree of crosslinking is determined without the need for complicated procedures for preparing, conditioning or configuring the test sample. The degree of crosslinking is determined by comparing the heat of the crosslinking reaction for the test sample with that of a reference sample, using a
15、 differential scanning calorimeter.The advantages of this method are that sample preparation is simple and measurements can be made with very small amounts of sample. For these reasons, this International Standard is useful for investigations of, and in establishing conditions for, crosslinking reac
16、tions. It can also be used for production and quality control.Finally, since epoxy resin systems are highly diverse, the applicability of this International Standard to each resin system needs be established. A technique to test the applicability to an epoxy resin system is included in the standard.
17、iv ISO 2012 All rights reservedBS ISO 14322:2012Plastics Epoxy resins Determination of degree of crosslinking of crosslinked epoxy resins by differential scanning calorimetrySAFETY STATEMENT Persons using this document should be familiar with normal laboratory practice, if applicable. This document
18、does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any regulatory requirements.1 ScopeThis International Standard specifies a method whereby t
19、he heat of reaction generated during epoxy resin crosslinking is measured by differential scanning calorimetry (DSC). The degree of crosslinking is determined based on this result.This method is applicable to epoxy resin systems with a moderate or slow crosslinking-reaction speed. It might not be ap
20、plicable to systems with a fast crosslinking-reaction speed at ambient temperature.2 Normative referencesThe 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
21、referenced document (including any amendments) applies.ISO 11357-1:2009, Plastics Differencial scanning calorimetry (DSC) Part 1: General principlesISO 11409:1993, Plastics Phenolic resins Determination of heats and temperatures of reaction by differential scanning calorimetry3 Terms and definitions
22、For the purposes of this document, the terms and definitions given in ISO 11357-1 and the following apply.3.1degree of crosslinkingvalue, calculated in accordance with Equation (2) in Clause 8, which indicates the extent of the crosslinking reaction of an epoxy resin system, expressed as a percentag
23、e3.2uncrosslinked epoxy resin systemepoxy resin system immediately after mixing the system components, before any crosslinking has taken place3.3total heat of reactiongross amount of reaction heat produced by an uncrosslinked epoxy resin system (see 3.2) during complete crosslinking, as determined b
24、y DSC, expressed in joules/gram4 PrincipleThe total heat of reaction is first measured by DSC, using a test sample taken from the uncrosslinked epoxy resin system. Curve A in Figure 1 is an example of such a DSC curve.The heat of reaction of a test sample of the (partly) crosslinked resin system und
25、er investigation is then measured, using the same DSC apparatus and under the same conditions as those used to measure the INTERNATIONAL STANDARD ISO 14322:2012(E) ISO 2012 All rights reserved 1BS ISO 14322:2012ISO 14322:2012(E)total heat of reaction, in order to determine the heat of reaction due t
26、o the remaining reactive groups as the reaction goes to completion. Curves B1 and B2 in Figure 1 are examples of DSC curves obtained with such test samples.Curve B1 shows a case where crosslinking did not progress to a large extent before the DSC measurement and curve B2 shows a case where crosslink
27、ing progressed considerably before the DSC measurement.The degree of crosslinking of the (partly) crosslinked resin system is determined from the heat of reaction of this crosslinked resin system and the total heat of reaction of the uncrosslinked resin system see Equation (2) in Clause 8.KeyX tempe
28、rature or timeY heat flow rate (exothermic)Figure 1 DSC curve (schematic)Crosslinking epoxy resin systems are highly diverse, and the systems to which this International Standard can be applied are limited due to measurement-related constraints of the method used. For example, the method cannot be a
29、pplied to a crosslinking epoxy resin system for which the reaction progresses too far before the system components can be thoroughly mixed and subjected to DSC measurement. In such a system, it is not feasible to determine the total heat of reaction accurately.For this reason, a preliminary test (se
30、e 7.2) is used in order to determine if this International Standard is applicable to the epoxy resin system of interest.5 Materials5.1 Calibration material, selected in accordance with ISO 11357-1:2009, 8.2.NOTE Indium is typically used.2 ISO 2012 All rights reservedBS ISO 14322:2012ISO 14322:2012(E
31、)5.2 Epoxy resin system, including the following:5.2.1 Epoxy resin, as specified in the test resin system formulation.5.2.2 Hardener, as specified in the test resin system formulation.5.2.3 Catalyst, as specified in the test resin system formulation.6 Apparatus6.1 DSC apparatus, having the following
32、 characteristics:a) a heating rate of up to 10 C per minute;b) automatic recording of the differential heat flow between the test sample and the reference material;c) the ability to measure heat flux or energy difference with a minimum precision of 1 %;d) the ability to measure the test sample tempe
33、rature to within 0,1 C;e) an operating range extending at least from 20 C to 300 C.6.2 Gas flow device, constructed such that the gas flows around the test sample, and including a gas flow meter capable of measuring the gas flow rate in a range from 10 ml to 50 ml per minute.6.3 Sample holder (pan),
34、 made from a material with a high thermal conductivity, which is not eroded by the test sample.6.4 Recorder, capable of recording DSC curves automatically.6.5 Analytical balance, capable of weighing to 0,01 mg.7 Procedure7.1 CalibrationCalibration shall be in accordance with ISO 11357-1:2009, Clause
35、 8.7.2 Preliminary test7.2.1 This International Standard is applicable to crosslinking epoxy resin systems for which acceptable agreement is obtained between the total heat of reaction for two test samples which are taken at the same time from the same uncrosslinked epoxy resin system and are measur
36、ed consecutively under the same conditions using the same DSC apparatus.7.2.2 Mix well the epoxy resin system components (epoxy resin and other ingredients) to produce a mixture of the uncrosslinked epoxy resin system under test.7.2.3 Using an analytical balance, immediately weigh out, to the neares
37、t 0,01 mg, a 10 mg to 20 mg test sample from this mixture and put it into the pan of the DSC apparatus. ISO 2012 All rights reserved 3BS ISO 14322:2012ISO 14322:2012(E)7.2.4 Carry out the DSC measurement in accordance with a previously developed time-temperature programme. The programme defines the
38、starting temperature, the heating rate, the final temperature and the cooling time. Calculate the total heat of reaction (HT1) as specified in ISO 11409:1993, 4.5.3.1.NOTE A starting temperature which is at least 30 C below the temperature at which the crosslinking reaction begins, a heating rate of
39、 10 C/min and final temperature of 250 C have been used successfully.7.2.5 Immediately after the first measurement, cool down the apparatus at cooling rate about 30 C/min.7.2.6 From the mixture prepared in 7.2.2, weigh out a second test sample in the same way as described in 7.2.3 and carry out a se
40、cond DSC measurement under the same conditions as were used for the first test sample. Calculate the total heat of reaction (HT2) for this second test sample as specified in ISO 11409:1993, 4.5.3.1.7.2.7 If HT1and HT2satisfy the following inequality, this International Standard is applicable to the
41、epoxy resin system concerned. In this case, proceed to 7.3 for the measurement of the DSC curve given by the (partly) crosslinked resin.HHHHTTTT12122100 10+()% (1)NOTE An example of a preliminary test is given in Annex A.7.3 DSC measurement on the crosslinked resin under investigation7.3.1 Using an
42、analytical balance, weigh, to the nearest 0,01 mg, 10 mg to 20 mg of the (partly) crosslinked resin and put it into the pan of the DSC apparatus.7.3.2 Carry out the DSC measurement under the same conditions as in the preliminary test (see 7.2) and calculate the heat of reaction as specified in of IS
43、O 11409:1993, 4.5.3.1.7.3.3 Repeat the measurement with a second test sample of the (partly) crosslinked resin and determine the average of the heats of reaction obtained in the two measurements. This average is used as the heat of reaction of the crosslinked sample (HS) in the calculation in Clause
44、 8.8 Expression of resultsCalculate the degree of crosslinking as follows:Degree of crosslinking (%) = 1 100HHST(2)whereHTis the total heat of reaction obtained from the preliminary test described in 7.2 (the average of the two measured values HT1and HT2) (J/g);HSis the heat of reaction of the (part
45、ly) crosslinked resin (the average of the two measured values as determined in 7.3) (J/g).9 Precision9.1 GeneralPrecision data were determined from a round-robin experiment organized in 2007 involving six laboratories in Japan.4 ISO 2012 All rights reservedBS ISO 14322:2012ISO 14322:2012(E)9.2 Mater
46、ials and crosslinking conditions Epoxy resin: Bisphenol-A-type epoxy resin; hardener: acid anhydride. Three different samples were tested, obtained by different crosslinking conditions: 100 C for 60 min, 100 C for 90 min and 150 C for 120 min.9.3 Precision of the methodThe resulting data, which were
47、 analysed in accordance with ISO 5725-2, are given in Table 1.Table 1 Precision dataSamples(crosslinking conditions)Degree of crosslinking, % (averaged)RepeatabilitysrReproducibilitysRSample A(100 C for 60 min)69,3 1,24 3,14Sample B(100 C for 90 min)84,6 0,95 5,23Sample C(150 C for 120 min)98,1 0,69
48、 1,9410 Test reportThe test report shall include the following information:a) a reference to this International Standard;b) all details necessary for the identification of the epoxy resin system investigated, e.g. epoxy resin, hardener, catalyst;c) a description of the DSC apparatus used;d) the heat
49、ing rate used;e) the results of the preliminary test (see 7.2);f) the method used to integrate the area under each curve;g) the degree of crosslinking of the epoxy resin system investigated, calculated as specified in Clause 8;h) copies of the DSC curves obtained;i) the date of the test. ISO 2012 All rights reserved 5BS ISO 14322:2012ISO 14322:2012(E)Annex A (informative) Example of a procedure used for the preliminary test, with typical operating conditions6 ISO 2012 All rights reser
