1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication BS ISO 6721-11:2012 Plastics Determination of dynamic mechanical properties Part 11: Glass transition temperatureBS ISO 6721-11:2012 BRITISH STANDARD National foreword This Br
2、itish Standard is the UK implementation of ISO 6721-11:2012. The UK participation in its preparation was entrusted to Technical Committee PRI/21, Testing of plastics. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport
3、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 2012 ISBN 978 0 580 65186 1 ICS 83.080.01 Compliance with a British Standard cannot confer immunity from legal obligati
4、ons. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2012. Amendments issued since publication Date T e x t a f f e c t e dBS ISO 6721-11:2012 ISO 2012 Plastics Determination of dynamic mechanical properties Part 11: Glass transition
5、 temperature Plastiques Dtermination des proprits mcaniques dynamiques Partie 11: Temprature de transition vitreuse INTERNATIONAL STANDARD ISO 6721-11 First edition 2012-04-01 Reference number ISO 6721-11:2012(E)BS ISO 6721-11:2012ISO 6721-11:2012(E) ii ISO 2012 All rights reserved COPYRIGHT PROTECT
6、ED DOCUMENT ISO 2012 All 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 permission in writing from either ISO at the address below or ISOs memb
7、er body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in SwitzerlandBS ISO 6721-11:2012ISO 6721-11:2012(E) Foreword ISO (the International Organization for Standar
8、dization) 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 technical committee has been established has the right to
9、 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 of electrotechnical standardization. International Stan
10、dards 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 to the member bodies for voting. Publication as an Int
11、ernational 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 identifying any or all such patent rights. ISO 6721-
12、11 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2, Mechanical properties. ISO 6721 consists of the following parts, under the general title Plastics Determination of dynamic mechanical properties: Part 1: General principles Part 2: Torsion-pendulum method Part 3: Flexural
13、 vibration Resonance-curve method Part 4: Tensile vibration Non-resonance method Part 5: Flexural vibration Non-resonance method Part 6: Shear vibration Non-resonance method Part 7: Torsional vibration Non-resonance method Part 8: Longitudinal and shear vibration Wave-propagation method Part 9: Tens
14、ile vibration Sonic-pulse propagation method Part 10: Complex shear viscosity using a parallel-plate oscillatory rheometer Part 11: Glass transition temperature Part 12: Compressive vibration Non-resonance method ISO 2012 All rights reserved iiiBS ISO 6721-11:2012ISO 6721-11:2012(E) Introduction Thi
15、s part of ISO 6721 covers the use of dynamic mechanical analysis (DMA) procedures, in the temperature scanning mode, to determine a value for the glass transition temperature of plastics. It provides an alternative procedure to the use of differential scanning calorimetry (DSC) (see ISO 11357-2) for
16、 this measurement. DMA is used to determine the variation of the storage modulus, loss modulus and tan delta as a function of temperature and frequency. From these data, a value for the glass transition is determined. Many types of commercial equipment are available that use this technique and, in p
17、rinciple, it applies to all the loading modes described in ISO 6721-1. The procedures minimize errors due to thermal lag of the specimen, which varies with the heating rate used, through assuming the specimen temperature is given by the measured oven temperature 1) . This eliminates the need for the
18、 temperature of the specimen to be measured directly by, for example, a thermocouple embedded in the specimen. 1) See Sims G.D., Gnaniah S.J.P., Calibration Procedures for Increased Confidence in DMA Measurements, ICCM 11, Edinburgh, July 2009. iv ISO 2012 All rights reservedBS ISO 6721-11:2012Plast
19、ics Determination of dynamic mechanical properties Part 11: Glass transition temperature WARNING The use of this part of ISO 6721 may involve hazardous materials, operations and equipment. The document does not purport to address all of the safety problems associated with its use. It is the responsi
20、bility of the user to establish appropriate health and safety practices and to determine the applicability of regulatory limitations prior to its use. 1 Scope This part of ISO 6721 specifies methods for determining a value of the glass transition temperature (T g ) from the dynamic mechanical proper
21、ties measured during a linear temperature scan under heating conditions. The glass transition temperature is an indicator of the transition from a glassy state to a rubbery state. Usually referred to as dynamic mechanical analysis (DMA), the methods and their associated procedures can be applied to
22、unreinforced and filled polymers, foams, rubbers, adhesives and fibre-reinforced plastics/composites. Different modes (e.g. flexure, compression, tension) of dynamic mechanical analysis can be applied, as appropriate, to the form of the source material. NOTE For tests undertaken in the flexure or to
23、rsion mode, an additional procedure is included to identify the severity of the influences of thermal lag on the measured data (see Annex B). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited
24、 applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6721-1:2011, Plastics Determination of dynamic mechanical properties Part 1: General principles 3 T erms and definitio ns For the purposes of this document, the terms and definitio
25、ns given in ISO 6721-1 and the following apply. 3.1 glass transition temperature T g temperature of the point of inflection of the decrease in the storage modulus curve corresponding to the transition NOTE 1 This temperature often agrees with the temperature at the peak of the loss modulus data. NOT
26、E 2 It is expressed in degrees Celsius (C). NOTE 3 See Figure 1, data point 1. INTERNATIONAL STANDARD ISO 6721-11:2012(E) ISO 2012 All rights reserved 1BS ISO 6721-11:2012ISO 6721-11:2012(E) 3.2 temperature at onset T onset temperature corresponding to the onset of the transition from glassy state,
27、as defined by the intercept of two tangents in the storage modulus curve NOTE 1 The first tangent is extrapolated from a linear portion of the curve prior to the transition, and the second tangent is extrapolated from the point of inflection of the decrease in the curve corresponding to the glass-ru
28、bber transition . NOTE 2 It is expressed in degrees Celsius (C). NOTE 3 See Figure 1, data point 5. 3.3 temperature at peak of loss modulus data T loss temperature of the peak of the loss modulus curve NOTE 1 It is expressed in degrees Celsius (C). NOTE 2 See Figure 1, data point 2. 3.4 temperature
29、at peak of tan delta data T tan delta temperature of the peak in the tan delta curve NOTE 1 It is expressed in degrees Celsius (C). NOTE 2 See Figure 1, data point 3. 3.5 reference glass transition temperature T g(0) value of the extrapolated temperature at 0 C/min heating rate that is used for spec
30、 ific ation and c ontrac t requirements NOTE 1 It is expressed in degrees Celsius (C). NOTE 2 See Figure 2. 3.6 QA glass transition temperature T g(n) value taken from the calibration curve at n C/min heating rate that is used for quality assurance purposes, by agreement, with heating rate dependent
31、 equipment (i.e. not the extrapolated T g(0)value NOTE 1 It is expressed in degrees Celsius (C). NOTE 2 See 9.3.2. 4 Principle A specimen of known geometry is placed or held in a suitable mechanical loading system in an enclosed temperature chamber, or oven, that can be heated at a controlled rate.
32、The specimen is mechanically oscillated at a fixed frequency, and changes in the viscoelastic response of the material are monitored and recorded as a function of the test temperature. The dynamic properties (storage modulus, loss modulus and tan delta) are determined from the load and displacement
33、data recorded throughout the test (see ISO 6721-1). The glass transition temperature (T g ) is determined as the point of inflection in the storage modulus vs. the temperature plot. The test procedure described minimizes errors due to the thermal lag, which varies with the heating rate used, of the
34、specimen temperature through assuming the specimen temperature is given by the measured oven temperature. 2 ISO 2012 All rights reservedBS ISO 6721-11:2012ISO 6721-11:2012(E) 5 Equipment 5.1 Dynamic mechanical analyser The test equipment shall be capable of heating at rates from 1 C/min to 10 C/min
35、over the required temperature range and mechanically oscillating the specimen at the reference frequency of 1 Hz. The equipment should be capable of applying the temperature ramp profile to within 5 % of the required heating rate. The instrument shall continuously monitor and record the load applied
36、 to the specimen, and the corresponding displacement as a function of the measured temperature, in order to determine the storage modulus, loss modulus and tan delta. The load and displacement capabilities of the equipment shall be sufficient for the specimens tested. The equipment shall be calibrat
37、ed, as required by the equipment user manual see Annex A. 5.2 Devices for measuring test specimen dimensions These shall be in accordance with ISO 6721-1:2011, 5.6. 6 Test specimen 6.1 General The test specimen shall be in accordance with ISO 6721-1:2011, 6.1. 6.2 Shape and dimensions The dimensions
38、 of the specimen shall be as required by the equipment for the selected test mode. 6.3 Preparation The preparation of the test specimen shall be in accordance with ISO 6721-1:2011, 6.3. ISO 2012 All rights reserved 3BS ISO 6721-11:2012ISO 6721-11:2012(E) 6 1 7 3 2 5 4 100 0 M M tan 2 500 0 500 T 180
39、 Key 1 inflection point (storage modulus) ( = T g ) T temperature, C 2 peak (loss modulus) ( = T loss ) M storage modulus, MPa 3 peak (tan delta) ( = T tan delta ) M loss modulus, MPa 4 start point (storage modulus) tan tan delta 5 onset (storage modulus)( = T onset ) 6 endset (storage modulus) 7 en
40、d point (storage modulus) Figure 1 Plot of dynamic mechanical data against temperature 7 Number of specimens This shall be in accordance with ISO 6721-1:2011, Clause 7. Prepare additional specimens (at least three) to assess the heating rate dependency of the method according to Clause 9.2 8 Conditi
41、oning This shall be in accordance with ISO 6721-1:2011, Clause 8. 4 ISO 2012 All rights reservedBS ISO 6721-11:2012ISO 6721-11:2012(E) 9 Test procedure 9.1 Test atmosphere This shall be in accordance with ISO 6721:2011, 9.1 NOTE Measurements can be undertaken under static air conditions or an inert
42、atmosphere. However, it is important that the calibration and the specimen tests be performed under identical conditions. 9.2 Assessment of heating rate dependence 9.2.1 Heating rate dependence Procedure Calibrate the instrument in accordance with Annex A. Position the temperature sensor in the inst
43、rument as closely as possible to the sample under test, but ensuring it is not touching it. The position of the sensor shall remain undisturbed for subsequent specimen tests. If moved, recalibration may be necessary (see Annex A). Undertake tests according to Method A (see 9.3.1) to assess the heati
44、ng rate dependence of the material/equipment. 9.2.2 Heating rate dependence Results If the temperature at the inflection points is shown to vary by more than 2 C between the different heating rates, use Method A (see 9.3.1). NOTE For this case, a quality assurance procedure to reduce the testing tim
45、e is also available (see 9.3.2). If the results are shown to vary by less than 2 C between the different heating rates, use Method B (see 9.3.3). 9.3 Operation 9.3.1 Method A Rate-dependent results Mount the specimen into the instrument. Apply a constant rate temperature scan from at least 50 C belo
46、w to 50 C above the transition region(s) of interest at heating rates of 3 C/min, 5 C/min and 10 C/min. Use a new specimen for each heating rate. The reference test frequency of 1 Hz shall be used. The load/displacement on the specimen shall be selected so that the specimen deformation is within the
47、 elastic range of the material being tested. The applied level shall remain constant to within 10 % of the initial value applied. Record the load and displacement data as a function of temperature, so that the storage modulus, loss modulus and tan delta can be calculated and plotted against temperat
48、ure (see Figure 1). Determine the temperature at the inflection point for the storage modulus curve (see Figure 1, data point 1) at each heating rate. Plot the temperature of the inflection points as a function of heating rate, as shown in Figure 2. Extrapolate the data to meet the y-axis at 0 C/min
49、 using a linear fit. Report the extrapolated value to 0 C/min as T g(0) . These data form the “calibration curve” shown in Figure 2. NOTE The determination of the extrapolation value can be aided by an additional scan at 1 C/min, but care is needed if the material state (e.g. degree of cure) changes during the scan. ISO 2012 All rights reserved 5BS ISO 6721-11:2012ISO 6721-11:2012(E) 024 6810 12 180 200 T n T g(0) Key n heating rate, C/min
