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1、BRITISH STANDARD BS ISO 11357-3:1999 Plastics Differential scanning calorimetry (DSC) Part 3: Determination of temperature and enthalpy of melting and crystallization ICS 83.080.01 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357
2、-3:1999 This British Standard, 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 June 1999 BSI 03-2000 ISBN 0 580 32650 0 National foreword This British Standard repro
3、duces verbatim ISO 11357-3:1999 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/Eur
4、opean committee any enquiries 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.
5、Cross-references The British Standards which implement international 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 Catalo
6、gue. A British 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 compr
7、ises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 4, an inside back cover 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 insid
8、e front cover. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-3:1999 BSI 03-2000i Contents Page National forewordInside front cover Forewordiii Text of ISO 11357-31 Licen
9、sed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Un
10、controlled Copy, (c) BSI BS ISO 11357-3:1999 ii BSI 03-2000 Contents Page Forewordiii 1Scope1 2Normative references1 3Definitions1 4Principle2 5Apparatus and materials2 6Test specimens2 7Test conditions and specimen conditioning2 8Calibration2 9Procedure2 10Expression of results3 11Precision4 12Test
11、 report4 BibliographyInside back cover Figure 1 Examples of characteristic temperature determinations1 Figure 2 Determination of the enthalpy of a transition3 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-3:1999 BSI 03-2000iii
12、 Foreword ISO (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
13、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 Electrotechnical Commission (IEC) on all matter
14、s of electrotechnical standardization. Draft International Standards adopted 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. International Standard ISO 11357-3
15、 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-chemical 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 temper
16、ature; Part 3: Determination of temperature and enthalpy of melting and crystallization; Part 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; Pa
17、rt 7: Determination of crystallization kinetics; Part 8: Determination of amount of water absorbed by polymers. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:0
18、0 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-3:1999 BSI 03-20001 WARNING The use of this 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 t
19、he user of this part of ISO 11357 to establish appropriate health and safety practices and 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 temperature and enthalpy of melting and crystallization of
20、crystalline or semi-crystalline plastics. 2 Normative references The following standards contain provisions 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, an
21、d parties to agreements based on this part of ISO 11357 are encouraged to investigate the possibility of 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 atmospher
22、es for conditioning and testing. ISO 472:, Plastics Vocabulary1). ISO 11357-1:1997, Plastics Differential 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 melting the t
23、ransition stage between a fully crystalline or partially crystalline solid state and a liquid of variable viscosity NOTEThe transition, also referred to as fusion, is characterized by an endothermic peak in the DSC curve. 3.2 crystallization the transition stage between the amorphous liquid state an
24、d a fully crystalline or partially crystalline solid state NOTEThe transition is characterized by an exothermic peak in the DSC curve. An exception to this definition is the case of liquid crystals, where the term “amorphous liquid” should be replaced by “ordered liquid”. 3.3 enthalpy of fusion the
25、heat required to melt a material at constant pressure, measured in kJ/kg 1) To be published. (Revision of ISO 472:1988) Figure 1 Examples of characteristic temperature determinations Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 113
26、57-3:1999 2 BSI 03-2000 3.4 enthalpy of crystallization the heat released by the crystallization of a material at constant pressure, measured in kJ/kg 3.5 characteristic temperatures the following temperatures (see Figure 1): NOTEThe additional subscript m is used to denote temperatures related to t
27、he melting phenomenon and the subscript c to denote temperatures related to the crystallization phenomenon. 4 Principle See ISO 11357-1:1997, clause 4. 5 Apparatus and materials See ISO 11357-1:1997, clause 5. The gas supply shall be analytical grade nitrogen or another inert gas. All specimens and
28、pans shall be handled using clean tweezers. 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. 9 Procedure 9.1 Setting up the apparatus See ISO 11357-1:1997, subclause 9.1. Switch
29、on apparatus and allow it to equilibrate for at least 30 min. Use the same purge gas flow rate that was used to calibrate the instrument. Any change in flow rate or gas requires re-calibration. Typically, nitrogen gas (analytical grade) at a flow rate of 50 ml/min 10 % is used. Other inert gases and
30、 flow rates may be used by agreement between the interested parties. 9.2 Loading the test specimen into the pan See ISO 11357-1, subclause 9.2. Unless otherwise specified in the materials document, use a mass of 5 mg to 10 mg for the measurement. The accuracy of weighing shall be to the nearest 0,1
31、mg. 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 tweezers or wear gloves. 9.3 Insertion of pans See ISO 11357-1:1997, subclause 9.3. 9.4 Tempe
32、rature 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 high enough to erase the test materials previous thermal history, typically 30 C above the extrap
33、olated end melting temperature (Tefm). 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 heat scan (see Annex B
34、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 report. 9.4.3 Hold the temper
35、ature for 5 min. 9.4.4 Perform and record a cooling cycle at a rate of 20 C/min to approximately 50 C below the extrapolated end crystallization temperature (Tefc). NOTE 1Other heating or cooling rates may be used by agreement between interested parties. In particular, high scanning rates result in
36、better sensitivity of the recorded transition. On the other hand low scanning rates provide better resolution and may be appropriate in the resolution of closely overlapping transitions. NOTE 2Because of supercooling, crystallization does not occur until a sufficient temperature gradient is availabl
37、e, usually significantly below the melting 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 (see note 1 to 9.4.4) to approximately 30 C higher than the extrapolated end melting temperature (Tefm). 9.4.7 Bring the apparatus to am
38、bient 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. extrapolated onset temperatureTei peak temperatureTp extrapolated end temperatureTef Licensed Copy: sheffieldun sheffieldun
39、, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-3:1999 BSI 03-20003 9.4.9 If any weight loss has occurred, 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
40、 a lower maximum temperature. Do not reuse pans showing signs of deterioration for another measurement. If the test specimen overflows during measurement, clean the specimen holder assembly, following the instrument manufacturers instructions, and confirm that the calibration is still valid using at
41、 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 results 10.1 Determination of transition temperatures Scale the plot so that the peak cov
42、ers at least 25 % of full scale. Construct a baseline to the peak by joining the two points at which the peak (endothermic peak for fusion, exothermic peak for crystallization) begins to deviate from the relatively straight baseline, as shown in Figure 1. If multiple peaks are present, draw a baseli
43、ne to each. For a melting transition curve, measure and report the following for each peak: NOTEThe extrapolated onset temperature (Tei) is where the extrapolated baseline is intersected by the tangent to the curve at the point of inflection and corresponds to the start of the transition. The extrap
44、olated end temperature (Tef) is where the extrapolated baseline is intersected by the tangent to the curve at the point of inflection and corresponds to the end of the transition. The peak temperature (Tp) is the temperature at which the peak reaches a maximum (or minimum). 10.2 Determination of ent
45、halpies (see Figure 2) Measure the area under the peak to the baseline constructed as described in 10.1 Calculate the enthalpy of fusion %Hf (enthalpy of crystallization %Hc), in kJ/kg, using the following equation: where NOTE 1Modern equipment will perform this calculation. NOTE 2In the event of si
46、gnificant differences between the specific heat capacities of the solid and liquid states of the polymer, the use of special types of baseline, such as sigmoid baselines, may improve the results. the extrapolated onset melting temperature Teim the peak melting temperatureTpm the extrapolated end mel
47、ting temperature Tefm For a crystallization transition curve, measure and report the following for each peak: the extrapolated onset crystallization temperature Teic the peak crystallization temperatureTpc the extrapolated end crystallization temperature Tefc Figure 2 Determination of the enthalpy o
48、f a transition %His the enthalpy of fusion or crystallization of the specimen (kJ/kg); %HSis the enthalpy of fusion or crystallization of the standard (kJ/kg); Ais the peak area for the specimen (mm2); ASis the peak area for the standard (mm2); Wis the mass of the specimen (mg); WSis the mass of the
49、 standard (mg); Tis the y-axis sensitivity of the specimen (mW/mm); TSis the y-axis sensitivity of the standard (mW/mm); Bis the x-axis sensitivity (time base) of the specimen (s/mm); BSis the x-axis sensitivity (time base) of the standard (s/mm). Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:08:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11357-3:1999 4 BSI 03-2000 11 Precision The precision of this test method is not known because inter-laboratory data are not available. When inter-labora