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1、BRITISH STANDARD BS ISO 11357-2:1999 Plastics Differential scanning calorimetry (DSC) Part 2: Determination of glass transition temperature ICS 83.080.01 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-2:1999 This British Standa
2、rd, having been prepared under the direction of the Sector Committee for Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 July 1999 BSI 03-2000 ISBN 0 580 32629 2 National foreword This British Standard reproduces verbatim ISO 11357-2:
3、1999 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee PRI/21, Testing of plastics, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiri
4、es on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The Britis
5、h Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British
6、Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front co
7、ver, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 4 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued sinc
8、e publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-2:1999 BSI 03-2000i Contents Page National forewordInside front cover Forewordiii Text of ISO 11357-21 Licensed Copy: sheffieldun sheffieldun, na
9、, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357
10、-2:1999 ii BSI 03-2000 Contents Page Forewordiii 1Scope1 2Normative references1 3Definitions1 4Principle1 5Apparatus and materials1 6Test specimens1 7Test conditions and specimen conditioning1 8Calibration1 9Procedure2 10Expression of results3 11Precision3 12Test report3 Bibliography4 Figure 1 Examp
11、les of characteristic glass transition temperature determinations2 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-2:1999 BSI 03-2000iii Foreword ISO (the International Organization for Standardization) is a worldwide federation
12、 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 be represented on that committee.
13、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. Draft International Standards adopted by the technica
14、l 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. International Standard ISO 11357-2 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-chemic
15、al properties. ISO 11357 consists of the following parts, under the general title Plastics Differential scanning calorimetry (DSC): Part 1: General principles; Part 2: Determination of glass transition temperature; Part 3: Determination of temperature and enthalpy of melting and crystallization; Par
16、t 4: Determination of specific heat capacity; Part 5: Determination of reaction temperatures, reaction times, heats of reaction and degrees of conversion; Part 6: Determination of oxidation induction, time; Part 7: Determination of crystallization kinetics; Part 8: Determination of amount of water a
17、bsorbed by polymers. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-2:1999 BSI 03-20001 WARNING The use of this
18、 part of ISO 11357 may involve hazardous materials, operations or equipment. This part of ISO 11357 does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this part of ISO 11357 to establish appropriate health and safety practices and
19、to determine the applicability of regulatory limitations prior to use. 1 Scope This part of ISO 11357 specifies a method for the determination of the characteristic glass transition temperatures of amorphous and semi-crystalline plastics. 2 Normative references The following standards contain provis
20、ions which, through reference in this text, constitute provisions of this part of ISO 11357. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 11357 are encouraged to investigate the possibility o
21、f applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 291:1997, Plastics Standard atmospheres for conditioning and testing. ISO 472:, Plastics Vocabulary1). ISO 11357-1:1997, Plastics Differenti
22、al scanning calorimetry (DSC) Part 1: General principles. 3 Definitions For the purposes of this part of ISO 11357, the definitions given in ISO 11357-1 apply, plus the following: 3.1 glass transition the reversible change in an amorphous polymer or in amorphous regions of a partially crystalline po
23、lymer from (or to) a viscous or rubbery condition to (or from) a hard and relatively brittle one 3.2 glass transition temperature the approximate midpoint of the temperature range over which the glass transition takes place NOTEThe assigned glass transition temperature (Tg) may vary, depending on th
24、e specific property and on the method and conditions selected to measure it. 3.3 Characteristic glass transition temperatures 3.3.1 extrapolated onset temperature Teig the point at which the extrapolated initial baseline on the low-temperature side of the curve is intersected by the tangent to the c
25、urve at the point of inflection 3.3.2 extrapolated end temperature Tefg the point at which the extrapolated initial baseline on the high-temperature side of the curve is intersected by the tangent to the curve at the point of inflection 3.3.3 midpoint temperature Tmg the point at which the curve is
26、intersected by a line that is equidistant between the two extrapolated baselines 4 Principle See ISO 11357-1:1997, clause 4. The change in specific heat capacity as a function of temperature is measured and the characteristic glass transition temperatures determined from the curve thus obtained. 5 A
27、pparatus and materials See ISO 11357-1:1997, clause 5. 6 Test specimens See ISO 11357-1:1997, clause 6. 7 Test conditions and specimen conditioning See ISO 11357-1:1997, clause 7. 8 Calibration See ISO 11357-1:1997, clause 8. 1) To be published. (Revision of ISO 472:1988) Licensed Copy: sheffieldun
28、sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-2:1999 2 BSI 03-2000 9 Procedure 9.1 Setting up the apparatus See ISO 11357-1:1997, subclause 9.1. Use the same purge gas flow rate that was used to calibrate the instrument. Any change in flow rate or gas r
29、equires re-calibration. Typically, nitrogen (analytical grade) at a flow rate of 50 ml/min 10 % is used. Other inert gases and flow rates may be used by agreement between the interested parties. Adjust the sensitivity so that the difference in vertical height across the transition zone (step) in the
30、 curve is at least 10 % of the full-scale reading of the recorder (modern instruments do not need this adjustment). 9.2 Loading the test specimen into the pan See ISO 11357-1:1997, subclause 9.2. Weigh the test specimen to the nearest 0,1 mg. Unless otherwise specified in the materials standard, use
31、 a mass between 5 mg and 20 mg. For semi-crystalline materials, use a mass near the higher limit. Ensure that the bottoms of the pans are flat. Good contact between the pans and the specimen holders is crucial to obtaining good data. Do not handle the test material or pan with bare hands; either use
32、 tweezers or wear gloves. 9.3 Insertion of pans See ISO 11357-1:1997, subclause 9.3. 9.4 Temperature scan 9.4.1 Allow 5 min for a nitrogen pre-purge prior to beginning the heating cycle. 9.4.2 Perform and record a preliminary thermal cycle at a rate of 20 C/min, heating the cell to a temperature hig
33、h enough to erase the test materials previous thermal history. DSC measurements on polymers are greatly affected by the thermal history and morphology of the sample and the test specimen. It is important that the preliminary heat cycle is performed and that the measurements are taken from the second
34、 heat scan (see Annex B of ISO 11357-1). In cases where the material is reactive or where it is desired to evaluate the properties of a specially pre-conditioned specimen, data may be taken during the first heating cycle. This deviation from the standard procedure shall be recorded in the test repor
35、t. 9.4.3 Hold the temperature for 5 min. 9.4.4 Quench cool to approximately 50 C below the anticipated glass transition temperature. 9.4.5 Hold the temperature for 5 min. 9.4.6 Perform and record a second heating cycle at a rate of 20 C/min, heating to approximately 30 C higher than the extrapolated
36、 end temperature (Tefg). NOTEOther heating or cooling rates may be used by agreement between the interested parties. In particular, high scanning rates result in better sensitivity of the recorded transition. On the other hand, low scanning rates provide better resolution. Appropriate selection of r
37、ate is important to the observation of subtle transitions. 9.4.7 Bring the apparatus to ambient temperature and remove the pans to determine if deformation of the pan or specimen overflow has occurred. 9.4.8 Reweigh the pan, with the test specimen, to within 0,1 mg. 9.4.9 If any weight loss has occu
38、rred, a chemical change should be suspected. Open the pan and inspect the test specimen. If the specimen has degraded, discard the test results and retest, selecting a lower maximum temperature. Do not reuse pans showing signs of deterioration for another measurement. Figure 1 Examples of characteri
39、stic glass transition temperature determinations Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-2:1999 BSI 03-20003 If the test specimen overflows during measurement, clean the specimen holder assembly, following the instrument
40、 manufacturers instructions, and confirm that the calibration is still valid using at least one temperature and enthalpy reference standard. 9.4.10 Process the data in accordance with the instrument manufacturers instructions. 9.4.11 Repeat testing shall be decided by the user. 10 Expression of resu
41、lts Determine the transition temperatures as shown in Figure 1. Often, the two baselines are not parallel. In such cases, Tmg is the point of intersection of the median line between the two extrapolated baselines with the curve. The point of inflection itself can also be determined as a characterist
42、ic glass transition temperature (Tg). It is obtained either by determining the maximum in the derivative DSC signal or by measuring the steepest slope in the transition zone. For curves showing an overshoot at the end of the transition (see the right-hand curve in Figure 1), the temperature determin
43、ation is identical. 11 Precision The precision of this test method is not known because inter-laboratory data are not available. When inter-laboratory data are obtained, a precision statement will be added at the following revision. 12 Test report See ISO 11357-1:1997, clause 10. Include as the test
44、 results item I), the characteristic glass transition temperatures Teig, Tefg and Tmg, in C, rounded to the nearest whole number. The glass transition temperature Tg corresponds to Tmg, but for most applications Teig is more meaningful and it is often referred to as Tg. It is important when stating
45、glass transition values that all the values Teig, Tefg and Tmg are reported. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-2:1999 4 BSI 03-2000 Bibliography 1 Turi, E. A., Thermal characterization of polymeric materials, 2nd E
46、d., Academic Press, 1996. 2 Wunderlich, B., Thermal analysis, Academic Press, 1990. 3 Perez, J., Physique et mcanique des polymres amorphes, Technique et Documentation, Edition Lavoisier (Paris), 1992. 4 Nakamura, S., et al., Thermal analysis of polymer samples by a round robin method I: Reproducibi
47、lity of melting, crystallization and glass transition temperatures, Thermochimica Acta, 136 (1988), pp. 163178. 5 Hatakeyama, T., and Quinn, F. X., Thermal analysis: Fundamentals and applications to polymer science, John Wiley & Sons, 1994. 6 Assignment of the glass transition, ASTM research report,
48、 1994. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:43 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-2:1999 BSI 389 Chiswick High Road London W4 4AL BSI British
49、Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an