INTERNATIONAL STANDARD ISO 11357-1 Third edition 2016-09-15 Plastics — Differential scanning calorimetry (DSC) — Part 1: General principles Plastiques — Analyse calorimétrique différentielle (DSC) — Partie 1: Principes généraux Reference number ISO 11357-1:2016(E) © ISO 2016 ISO 11357-1:2016(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2016, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2016 – All rights reserved ISO 11357-1:2016(E) Contents Page Foreword v Introduction vi Scope Normative references Terms and definitions Basic principles 8 4.1 4.2 4.3 General Heat-flux DSC Power-compensation DSC 7.1 7.2 Test conditions 11 Conditioning of specimens 11 8.1 8.2 8.3 General 11 Calibration materials 12 Temperature calibration 12 8.3.1 General 12 8.3.2 Procedure 12 8.3.3 Accuracy o f calibration 13 Heat calibration 13 8.4.1 General 13 8.4.2 Procedure 14 8.4.3 Accuracy o f calibration 14 Heat flow rate calibration 15 8.5.1 General 15 8.5.2 Procedure 15 Apparatus and materials Specimen 10 Test conditions and specimen conditioning 11 Calibration 11 8.4 8.5 Procedure 17 9.1 9.2 9.3 9.4 9.5 10 Setting up the apparatus 17 9.1.1 Switching on 17 9.1.2 Purge gas 17 9.1.3 Experimental conditions 17 9.1.4 Baseline determination 17 Loading the specimen into the crucible 17 9.2.1 General 17 9.2.2 Selection of crucibles 18 9.2.3 Weighing the specimen crucible 18 9.2.4 Loading the specimen 18 9.2.5 Determination of the mass of the specimen 18 Insertion of crucibles into the instrument 18 Performing measurements 18 9.4.1 General 18 9.4.2 Scanning mode 18 9.4.3 Isothermal mode 19 Post-run checks 20 9.5.1 Check for loss in mass 20 9.5.2 Inspection of specimens 20 9.5.3 Checking of crucibles and crucible holder 20 Test report 20 © ISO 2016 – All rights reserved iii ISO 1 7-1 : 01 6(E) (normative) (normative) (informative) (informative) (informative) 2 Annex B Extended, high-precision, heat calibration Annex C Recommended calibration materials Annex D Interaction of calibration materials with different crucible materials Annex E General recommendations Bibliography 3 Annex A iv Extended, high-precision, temperature calibration [1 ] © ISO 2016 – All rights reserved ISO 11357-1:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f 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 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 o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso.org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) Any trade name used in this document is in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary in formation The committee responsible for this document is ISO/TC 61, Plastics, Subcommittee SC 5, Physicalchemical properties This third edition cancels and replaces the second edition (ISO 11357-1:2009), 3.7.2 of which has been technically revised 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 and glass transition step height — Part 3: Determination of temperature and enthalpy of melting and crystallisation — Part 4: Determination of specific heat capacity — Part 5: Determination of characteristic reaction-curve temperatures and times, enthalpy of reaction and degree of conversion — Part 6: Determination ofoxidation induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT) — Part 7: Determination of crystallization kinetics © ISO 2016 – All rights reserved v ISO 113 57-1:2 016(E) Introduction ISO 11 57 pu rp o s e s , de s crib e s for routi ne thermo a na lytic a l che cks comp a rable data ne e de d for o f raw DSC te s t me tho d s materia l s a nd wh ich c a n b e fi n i s he d pro duc ts us e d or for for the qua l ity a s s u rance de term i nation of data she e ts or d atab a s e s T he pro ce du re s given i n I S O 11 apply a s long as product standards or standards describing special atmospheres for conditioning of specimens no t s p e ci fy o ther wi s e vi © ISO 2016 – All rights reserved INTERNATIONAL STANDARD ISO 11357-1:2016(E) Plastics — Differential scanning calorimetry (DSC) — Part 1: General principles SAFETY STATEMENT — Persons using this document should be familiar with normal laboratory practice, if applicable This document 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 Scope I S O 1 s p e c i fie s s evera l d i fferenti a l s c a n ni ng c a lori me tr y (D S C ) me tho d s for the therma l ana lys i s o f p olymers and p olymer blend s , s uch a s — thermopla s tic s ( p olymers , mou ld i ng comp ou nd s and o ther mou ld i ng materi a l s , with or without fi l lers , fibre s or rei n forcements) , — thermo s e ts (u nc u re d or c ure d materi a l s , with or without fi l lers , fibre s or rei n forcements) , a nd — ela s tomers (with or without fi l lers , fibre s or rei n forcements) ISO 11357 is intended for the observation and measurement of various properties of, and phenomena associated with, the above-mentioned materials, such as — phys ic a l tran s ition s ( glas s tra n s ition, pha s e tran s ition s s uch as melti ng and c r ys ta l l i z ation, p olymorph ic tran s ition s , e tc ) , — chem ic a l re ac tion s ( p olymeri z ation, cro s s l i n ki ng and c u ri ng o f ela s tomers a nd thermo s e ts , e tc ) , — the s tabi l ity to oxidation, a nd — the he at c ap acity T h i s p a r t o f I S O 1 s p e c i fie s a nu mb er o f genera l a s p e c ts o f d i fferenti a l s c a n ni ng c a lori me tr y, s uch as the principle and the apparatus, sampling, calibration and general aspects of the procedure and test report common to all following parts D e tai l s on p er form i ng s p e ci fic me tho d s a re given i n s ub s e quent p ar ts o f I S O 1 (s e e Foreword) Normative references T he fol lowi ng i nd i s p en s able c u ments , i n whole or i n p ar t, are normatively re ference d i n th i s c u ment a nd are for its appl ic ation For date d re ference s , on ly the e d ition cite d appl ie s For u ndate d re ference s , the late s t e d ition o f the re ference d c u ment (i nclud i ng any amend ments) appl ie s ISO 472, Plastics — Vocabulary ISO 80000-5, Quantities and units — Part 5: Thermodynamics Terms and definitions For the pu rp o s e s o f th i s c u ment, the term s and defi n ition s given i n I S O 47 and I S O 0 0 -5 and the fol lowi ng apply © ISO 2016 – All rights reserved ISO 1 7-1 : 01 6(E) differential scanning calorimetry DSC technique in which the di fference between the rate o f flow o f heat into a specimen crucible containing the specimen and that into a referen ce crucible (3.3) is derived as a function of temperature and/or time while the specimen and re ference are subjected to the same controlled temperature programme in a specified atmosphere using a symmetrical measurement system Note to entry: It is common practice to record, for each measurement run, a curve in which temperature or time is plotted as the abscissa and heat flow rate (3.4) difference as the ordinate The endothermic and/or exothermic direction is indicated on the DSC curve Note to entry: According to the principles o f thermodynamics, energy absorbed by a system is considered positive while energy released is negative This approach implies that the endothermic direction points upwards in the ordinate and the exothermic direction downwards (see Figures and 2) It also has the advantage that the direction of thermal effects in plots of heat flow rate (3.4) and specific heat is consistent 3.2 calibration material material for which one or more o f the thermal properties are su fficiently homogeneous and well established to be used for the calibration of a DSC instrument or for the assessment of a measurement method 3.3 reference crucible crucible used on the re ference side o f the symmetrical crucible holder assembly Note to entry: Normally, the re ference crucible is empty Note to entry: In special cases, such as the measurement o f highly filled or rein forced polymers or specimens having a heat capacity comparable to that o f the crucible, a suitable material can be used inside the re ference crucible This re ference material should be thermally inactive over the temperature and time range o f interest and its heat capacity should be similar to that o f the specimen In the case o f filled or rein forced products, the pure filler or rein forcement can be used, for example quantity o f heat trans ferred per unit time (d Q/d t) h e a t f l o w r a t e Note to entry: It is expressed in watts (W) or milliwatts (mW) Note to entry: The total quantity o f heat trans ferred, Q, corresponds to the time integral o f the heat flow rate: Q=∫ dQ dt dt 3.5 change in heat Q quantity o f heat absorbed (endothermic, Δ Q positive) or released (exothermic, Δ Q negative) within a specified time, t, or temperature, T, range by a specimen undergoing a chemical or physical change Δ and/or a temperature change: ∫ ∆Q = 60 T2 d Q dT β T1 d t or t2 d Q dt t1 d t ∆Q = ∫ © ISO 2016 – All rights reserved ISO 1 7-1 : 01 6(E) where Δ Q i s expre s s e d i n j ou le s ( J ) or a s a s p e ci fic quantity, Δ q, e xpre s s e d i n j ou le s p er amou nt o f materi a l i n gram s ( J⋅ g−1 ) or j ou le s p er amou nt o f materi a l i n mole s ( J⋅ mol −1 is the constant heating or cooling rate, dT/dt β ); , e xpre s s e d i n kelvi n s p er m i nute (K⋅ m i n −1 N o te to entr y: I f me a s u rements a re m ade at s ta nt p re s s u re , Δ Q ) cor re s p o nd s to the ch a nge i n enth a lp y, Δ H s p e c i f i c h e a t c a p a c i t y a t c o n s t a n t p r e s s u r e cp quantity o f he at ne ce s s ar y to i s e the temp erature o f un it ma s s o f materia l b y K at s tant pre s s u re: cp = or cp = where dQ dQ × m dT p 1 m × 60 d Q × β dt p i s the qua ntity o f he at, e xpre s s e d i n j ou le s ( J ) , ne ce s s a r y to rai s e the temp eratu re o f an amou nt of material of mass m T kelvins at constant pressure; ); β i s the he ati ng rate, expre s s e d i n kelvi n s p er m i nute (K⋅ m i n −1 cp i s expre s s e d i n j ou le s p er gra m p er kelvi n ( J⋅ g−1 ⋅ K−1 N o te to entr y: m , e xpre s s e d i n gram s (g) , b y d cp ) m ay a l s o b e e x pre s s e d i n j ou le s p er mole p er kelvi n ( J⋅ mol −1 ⋅ K−1 , is expressed in moles ) when the amount of material, N o te to entr y: When a n a l ys i n g p o l ymers , en s u re th at the me a s u re d s p e c i fic he at c ap ac ity e s no t i nclude a ny he at ch a n ge due to a chem ic a l re ac tio n o r a p hys ic a l tra n s ition baseline part of the recorded curve in which no reactions or transitions take place N o te to entr y: T h i s c a n b e a n i s o ther m a l b a s el i ne when the temp eratu re i s m a i nta i ne d co n s ta nt o r a dyn a m ic baseline when the temperature is changed in accordance with a controlled temperature programme 3.7.1 to 3.7.3 f f f Figure 1) N o te to entr y: T he b a s el i ne s de fi ne d i n re er to the qu a s i- s tation a r y nge o n l y, i e when the i n s tr u ment i s op erati n g u nder s tab le cond ition s s hor tl y a ter s ta r ti n g a nd s hor tl y b e ore end i ng the D S C r u n (s e e © ISO 2016 – All rights reserved ISO 1 7-1 : 01 6(E) Key d /d Q t T t heat flo w rate temperature time d /d vs (or ) vs specimen baselines Q T t t T t a virtual baseline instrument baseline quas i- s tatio nary range isothermal start baseline isothermal end baseline Endothermic direction Figure — Schematic drawing showing baselines 7.1 instrument b aseline c ur ve ob tai ne d u s i ng on ly emp ty cr ucible s o f identic a l mas s and materi a l i n the s p e c i men a nd re ference positions of the DSC cell N o te to entr y: T he i n s tr u ment b a s el i ne i s re qu i re d for he at c ap ac ity me a s u rements specimen baseline D S C c ur ve ob tai ne d outs ide any re ac tion or tra n s ition zone(s) wh i le the i n s tru ment i s lo ade d with b o th the specimen in the specimen crucible and the referen ce crucible N o te to entr y: I n th i s p a r t o f the c u r ve , the d i fference i n the referen ce crucible (3.3 (3.3) heat flow rate (3.4) between the specimen crucible and (3.7.1) ) dep end s s olel y on the he at c ap ac ity o f the s p e c i men a nd the in strum ent baselin e N o te to entr y: T he s p e c i men b a s el i ne re fle c ts the temp eratu re dep endence o f the he at c ap ac ity o f the s p e c i men N o te to entr y: For in strum ent baselin e he at c ap ac ity de ter m i n ation s , a dyn a m ic DSC c u r ve is re qu i re d (3.7.1) and the isothermal start and end baselines (see Figure 1) a nd, in add ition , the © ISO 2016 – All rights reserved ISO 11357-1:2016(E) 9.4.3.3 Specimen introduced at a temperature other than room temperature 9.4.3.3.1 S e t the Preparing the instrument i n s tru ment to conditions 9.4.3.3.2 the s p e ci fie d me a s u rement temp eratu re and a l low it to re ach s te ady- s tate Loading the specimen and carrying out the measurement run Introduce the crucible containing the specimen and that serving as reference into the crucible holder f f time To reduce uncontrolled transient changes in the temperature of the crucible holder, keep the time during which the crucible holder is open as short as possible Continue the run, with the test conditions at th i s temp eratu re and i m me d iately s tar t the i n s tru ment to re cord the D S C c u r ve as a u nc tion o unch ange d, unti l at le a s t m i n a fter the endo therm ic or exo therm ic re ac tion or tran s ition has fi n i s he d and a s table b a s el i ne i s ob tai ne d aga i n Re cord the he at flow rate data 9.4.3.3.3 for s ub s e quent eva luation Unloading the specimen Bring the instrument back to the loading temperature and remove the specimen crucible 9.4.3.3.4 Data processing Process the recorded data in accordance with the instrument manufacturer’s instructions and according to the thermal effects under investigation 9.5 Post-run checks 9.5.1 Check for loss in mass Reweigh the cr uc ible contai n i ng the s p e ci men a fter the te s t I f any lo s s i n ma s s i s ob s er ve d, th i s cou ld have created an additional thermal effect or perturbed the instrument baseline 9.5.2 Inspection of specimens I f a ny u ne xp e c te d chem ic a l change i s s u s p e c te d, op en the s p e c i men cr ucible a nd i n s p e c t the s p e c i men ca re fu l ly D o no t u s e damage d c rucible s for any fu r ther me a s u rements The re-use of crucibles is not recommended However, in exceptional circumstances, when it has been no residual contamination is left on removal of the specimen and that the crucibles are not damaged, unambiguou s ly demon s trate d th at there i s no i nterac tion b e twe en the s p e c i men s and the c rucible s , that then cruc ible s may b e re -u s e d T hei r re -u s e sh a l l b e rep or te d i n the te s t rep or t, however 9.5.3 Checking of crucibles and crucible holder E xam i ne the s p e c i men c rucible to che ck for any cha nge o f lo c ation with i n the cr ucible holder, any de formation o f the cr uc ib le or any over flow o f s p e ci men materi a l I f a ny o f the s e has o cc u rre d, rep e at the measurement run I f the cr uc ib le holder s b e en conta m i nate d from s p e ci men over flow or conden s e d volati le s ub s ta nce s , clean it in accordance with the manufacturer’s instructions and recalibrate it 10 Test report The test report shall include the following information: a) a reference to the relevant part of ISO 11357; b) 20 a l l i n formation ne ce s s ar y for comp le te identi fic ation o f the materia l exa m i ne d; © ISO 2016 – All rights reserved ISO 113 57-1:2 016(E) c) the typ e o f D S C i n s tr ument u s e d ( he at-flu x or p ower- comp en s ate d) , a s wel l as the i n s tru ment model and manufacturer; d) the typ e o f cruc ible u s e d, the c rucible materia l and, when ne ce s s a r y, the ma s s o f e ach c rucible; e) the purge ga s u s e d, its pu rity a nd the flow rate u s e d; f) the typ e o f c a l ibration pro ce du re u s e d (s i mple or ex tende d) and de tai l s o f the c a l ibration materi a l s j) the therma l h i s tor y o f the s ample a nd the s p e ci men; used, including source, mass and other properties important for calibration; g) details of sampling, specimen preparation and conditioning, if applicable; h) the shape and dimensions of the specimen, if applicable; i) the mass of the specimen; k) the temperature programme parameters, including the time and temperature of isothermal steps a nd the rate o f dynam ic s tep s; l) the ch ange i n ma s s , i f any, o f the s p e c i men du ri ng the te s t; m) the test results, including the DSC curves obtained; n) a ny add itiona l i n formation, i nclud i ng de tai l s o f any devi ation s from the pro ce du re and any op eration s no t s p e ci fie d i n the releva nt p a r t o f I S O 1 wh ich cou ld h ave h ad a n i n fluence on the results; o) the date of the test © ISO 2016 – All rights reserved 21 ISO 1 7-1 : 01 6(E) Annex A (normative) Extended, high-precision, temperature calibration [1 ] The extended temperature calibration shall be used if one or more of the following are required: — a pre ci s ion h igher than ± , K over a temp erature range o f K; — the inclusion of the effect of heating rate in the calibration procedure; — the i nclu s ion o f the i n fluence o f s p e c i men ma s s i n the ca l ibration pro ce du re Two specimens of each of at least three different calibration materials covering the temperature range required, with masses, m f f made of aluminium with an oxidized surface For each heating and cooling rate, β = K/min, K/min, 10 K/min and 20 K/min, the specimen shall melting peak shall be recorded For each peak, determine the extrapolated peak onset temperature, Tei,m (see Figure A.2), using the interpolated virtual baseline between peak onset and peak end For each calibration material and each mass, plot the extrapolated peak onset temperatures against the heating rate and extrapolate the plot in a straight line to the heating rate β = K/min (see Figure A.1) Tcorr(Tcal , m temperature thus determined, Tei,m( β = 0), from the true transition temperature, Tcal (see Figure A.1): ∆Tcorr (Tcal m ) = Tcal − Tei, m ( β = ) (A.1) , o approxi mately mg and 10 mg , sh a l l b e weighe d i nto c rucible s , pre erably b e melte d and re c r ys ta l l i ze d and then s ubj e c te d to a he ati ng ru n at the s ame rate, du ri ng wh ich the D e term i ne the temp eratu re corre c tion, Δ ), by s ub trac ti ng the ex trap olate d p e a k on s e t , Plo t the temp eratu re corre c tion term s de term i ne d b y th i s pro ce du re aga i n s t the e xtrap ol ate d p e a k onset temperatures, Tei,m( β = 0), to give the temperature dependence of the temperature calibration (see Figure A.2): ∆Tcorr (T, m ) = f[Tcal − Tei, m (Tcal , m, β = ) ] (A.2) NOTE The temperature correction with respect to the heating rate and/or temperature is made auto m atic a l l y b y s ome i n s tr u ments If wider temperature ranges are required, it is preferable to use more than three calibration materials T he acc u rac y o f th i s temp eratu re c a l ibration pro ce du re wou ld b e e xp e c te d to b e b e tter th an ± , K over a temp eratu re nge 22 from ° C to 3 ° C [13] © ISO 2016 – All rights reserved ISO 1 7-1 : 01 6(E) Key T β Tcal Tei,1 m ( β = ) , Tei,m ( β = 0) Tcorr Δ , Δ Tcorr temperature heating rate true transition temperature of calibration material (tin) peak onset temperatures extrapolated to zero heating rate for mg and 10 mg s p ecimen mas s es , res p ectively temp erature co rrectio ns fo r mg and mg s p ecimen mas s es , res p ectively Figure A.1 — D etermination of temperature correction from plots of extrapolated peak onset temperature versus heating rate using tin as calibration material Key Tcorr Tei,m(β = 0) Δ temperature correction peak onset temperature for calibration material extrapolated to zero heating rate Figure A — Temperature calibration function obtained with gallium, indium and tin © ISO 2016 – All rights reserved 23 ISO 1 7-1 : 01 6(E) Annex B (normative) Extended, high-precision, heat calibration The extended heat calibration shall be used if one or more of the following are required: — a pre ci s ion h igher than ± %; — the inclusion of the effect of heating rate in the calibration procedure; — the i nclu s ion o f the i n fluence o f s p e c i men ma s s i n the ca l ibration pro ce du re Annex A, draw a linear virtual baseline (see Figure 1) and determine the heat of melting from the area between the DSC curve and the virtual baseline using Formula (8) (see 8.4.2) Figure B.1 shows a heat calibration function obtained using gallium, indium and tin For e ach o f the p e a ks ob ta i ne d a s s p e c i fie d i n Key heat calibration factor, dependent on calibration material, specimen mass and heating rate T temperature calibration curve for specimen mass of mg and heating rate of K/min calibration curve for specimen mass of 10 mg and heating rate of K/min KQ Figure B — Heat calibration function determined with gallium, indium and tin The individual heat calibration factors, qcal materials: tra n s ition, Δ , by the me a s ure d KQ , s p e ci fic a re ob tai ne d he ats by d ivi s ion o f tran s ition, Δ qm o f the true s p e c i fic he ats of , of the respective calibration KQ (Tcal , m, β ) = ∆q cal / ∆q m (Tcal , m, β ) (B.1) where Tcal is the true transition temperature of the calibration material 24 © ISO 2016 – All rights reserved ISO 113 57-1:2 016(E) The heat calibration factors are plotted against temperature to obtain the heat calibration function (see Figure B.1): K Q (T, m, β ) = f[ ∆q cal / ∆q m (Tcal , m, β ) ] (B.2) If the dependencies on heating rate and/or mass are not negligible, these will have to be determined s ep arately T he acc u rac y o f th i s pro ce dure wou ld b e exp e c te d to b e b e tter tha n ± , % © ISO 2016 – All rights reserved [6] 25 ISO 1 7-1 : 01 6(E) Annex C (informative) Recommended calibration materials Table C — Transition temperature, heat of transition and type of transition for various recommended calibration materials [4] [6] M aterial Trans ition Heat of temp erature transition °C − 155,77 − 135,09 − 93,43 J⋅g−1 Typ e of transition 0,00 29,76 69,60 4,91 8,63 — 79,88 solid-solid solid-solid solid-liquid solid-liquid solid-liquid Indium Tin Bismuth 156,60 231,93 (271,40) 28,62 60,40 53,84 solid-liquid solid-liquid solid-liquid Lead Zinc Lithium sulfate 327,46 419,53 578,28 — — 228,1 solid-liquid solid-liquid solid-solid Cyclopentane Cyclopentane Cyclopentane Water Gallium Aluminium 660,32 398,1 solid-liquid Remarks Measure in a hermetically sealed crucible only Introduce as a liquid and reweigh to determine the mass Not suitable for heat calibration Melt reacts with Al Allow for strong supercooling Melt reacts with Al Melt reacts with Al Not suitable for temper- ature calibration Not suitable for heat calibration Not suitable for heat calibration Anhydrous compound is hygroscopic: weigh in as Li2 SO 4.H O Dehydration starts at 110 °C with brisk movement of the particles in the crucible High water vapour pressure (do not use hermetically sealed crucibles) Reweigh after measurement run to determine the mass Melt reacts strongly with Pt For other suitable calibration materials, refer to the recommendations of ICTAC 1) , GEFTA2) and NIST3) Certified calibration materials can be obtained from national metrological institutes (e.g LGC, PTB, NIST, LNE, NMIJ), instrument manu facturers or other qualified sources Do not re-use calibration materials that have, or might have, reacted with the crucible material 1) 2) 3) 26 International Con federation for Thermal Analysis and Calorimetry (ICTAC): http://www.ictac.org Gesellschaft für Thermische Analyse e.V (GEFTA): http://www.gefta.org National Institute o f Standards and Technology (NIST): http://www.nist.gov © ISO 2016 – All rights reserved ISO 1 7-1 : 01 6(E) Table C.2 — Recommended materials for heat flow rate calibration[5 ] [6] Temp erature Heat cap acity, ( ) cp T range M aterial K 70 to 300 Corundum (α-Al O ) ∑ i =0 290 to 250 Copper (Cu) ∑ i =0 20 to 97,5 ∑ ci i =0 97,5 to 320 is the temperature, in kelvins a , b , c and d f f ∑ di i =0 Ti bi T i % 0,4 to 0,1 0,1 O x yge n- fre e , h i gh- c o n duc ti v i t y qual ity No l imitation s on crucible material below its melting point 0,1 Ti the b e s t- fi t p o l yno m i a l s (s e e No limitations on crucible material below its melting point 0,1 to 0,2 Ti T a re the co e fic ients o [5] Remarks J⋅ g−1 ⋅ K−1 (s ynthe tic s app h i re) Uncertainty Table C.3) Table C.3 — Coe fficients o f the best-fit polynomials in Table C.2 for the heat capacity o f the heat flow rate calibration materials [5 ] [6] i a 3,632 45 × 10 b −2 − ,1 14 × 10 − , 1 × 10 −1 8,259 81 × 10 −3 − , 8 × 10 − 5,961 37 × 10 2,176 63 × 10 −7 2,502 51 × 10 −8 − , 41 × 10 −1 7,017 32 × 10 −1 − , 67 × 10 −3 − ,767 67 × 10 − − 4,9 × 10 − 1,830 01 × 10 c −14 −1 − , 676 × 10 1,684 86 × 10 −17 −1 1,437 45 × 10 d −2 − , 10 × 10 − , 70 × 10 −1 7,077 45 × 10 −3 − , 3 × 10 − 4,205 14 × 10 − ,7 × 10 − 9,607 53 × 10 −6 − ,49 × 10 − 6,714 59 × 10 −3 −8 − 9, 61 51 × 10 −1 −1 − ,9 71 × 10 −1 −2 Table C.4 — Specific heat capacity o f corundum in the temperature region from 290 K to 550 K (calculated using data from Tables C and C ) Temperature K 290 300 310 320 330 340 350 360 370 380 © ISO 2016 – All rights reserved Heat cap acity, ( ) cp T J⋅ g−1 ⋅ K−1 0,758 0,779 0,799 0,818 0,836 0,854 0,870 0,886 0,901 0,915 27 ISO 1 7-1 : 01 6(E) Table C Temp erature K 390 400 410 420 430 440 450 460 470 480 490 500 510 520 530 540 550 28 (continued) Heat cap acity, ( ) cp T J⋅g−1⋅K−1 0,929 0,941 0,954 0,965 0,976 0,987 0,997 1,007 1,016 1,025 1,033 1,041 1,049 1,056 1,063 1,069 1,076 © ISO 2016 – All rights reserved ISO 1 7-1 : 01 6(E) Annex D (informative) Interaction of calibration materials with different crucible materials The calibration materials recommended in Table C.1 materi a l s norma l ly u s e d for DSC In the s e cases, may there form is m i xe d pha s e s with s ome o f the cruc ible a ri s k o f a molten c a l ibration s p e ci men d i s s olvi ng s ome o f the cruc ible materi a l, wh ich may re s u lt i n a n u npre d ic table ch ange i n melti ng p oi nt and/or damage to the crucible Table D.1 can be inferred from the respective phase diagrams shows combi nation s i n wh ich i nterac tion s may o cc u r, wh ich Table D.1 — I nteraction of calibration and crucible materials [4] C alibration material C rucible material Corundum, Al O Boron nitride, BN Graphite, C Silicate glass Quartz glass, SiO2 Aluminium, Al Aluminium, oxidized Silver, Ag Gold, Au Nickel, Ni Iron, Fe Stainless steel Platinum, Pt M o lyb denu m , Mo Tantalum, Ta Tungsten, W C yclop entane Water Gal lium I ndium Tin Lead Zinc o o + + + + + o o + + + + o + + o + + + + + + + + + + + + + • + + + + + + + + + + + + + + • + + + • • • • • • + o + o ? • Lithium s ulfate Aluminium + + + + + + + + + ? + + + + + - + + + + + + x x • • + + • ? • • • • • + + ? • • ? + ? ? ? + ? ? + ? ? ? ? • ? + + ? • Key + no s o lub i l i t y a nd no i n fluence o n me l ti n g p o i nt to b e e x p e c te d; • x ? melt dissolves crucible material, resulting in greater change in melting point; partial-dissolution processes are possible with negligible change in melting point; crucible melts; interaction unknown; o her me tic s e a l i n g o f c r uc ib le m ay b e d i ffic u lt I t i s s trongly re com mende d th at tho s e combi nation s i n Table D.1 marked with a “-” should not be used b e c au s e d i s s olution o f the c rucible c an no t on ly i nva l idate the c a l ibration but a l s o damage the c rucible © ISO 2016 – All rights reserved 29 ISO 113 57-1:2 016(E) holder The combinations marked with a “+” should pre ferably be used for calibration A “•” indicates systems in which no significant falsification o f the temperature is to be expected, although, in these cases, a certain amount of caution is advisable with respect to the consequences of partial dissolution of the crucible material As can be seen from Table D.1, there is at least one crucible material suitable for each of the recommended calibration materials I f necessary, the crucible used can be coated with a protective layer for calibration purposes Aluminium oxide is ideally suited for this purpose In the case o f the aluminium crucibles normally used, this protective oxide layer can be produced in su fficient thickness by heating to 570 °C in air 30 © ISO 2016 – All rights reserved ISO 1 7-1 : 01 6(E) Annex E (informative) General recommendations This test method is suitable for comparative measurements on polymeric materials However, the results obtained may be influenced by systematic errors such as incorrect calibration, incorrect baseline correction and incorrect specimen preparation and conditioning It is strongly recommended that suitable polymeric re ference materials (similar to those materials routinely analysed) be analysed, for comparative purposes, in parallel with the materials being tested This allows data obtained from different laboratories, from different instruments, on different dates and using different specimen conditioning and preparation procedures, etc to be compared Except for special cases in which the decomposition o f polymers is the subject o f investigation, it is not recommended that measurements be continued beyond the decomposition temperature o f the polymer sample This decomposition may lead to the contamination o f the crucible holder assembly by materials in open or ventilated crucibles or to the explosion o f hermetically sealed crucibles At worst, the crucible holder assembly may be destroyed In addition to this, very high temperatures or large temperature-scanning ranges could cause alteration in the linearity o f the calibration settings, resulting in erroneous data The interpretation of a DSC curve indicating the occurrence of several thermal effects, such as glass transition steps or first-order transition peaks, is fairly straightforward when these e ffects are clearly separated Quite often, however, DSC curves will show steps and/or peaks that cannot be separated easily These types o f curve are a result o f several reactions and/or transitions which overlap or occur simultaneously In these cases, the only thermal properties that can be determined without using sophisticated curve separation procedures are the overall heat of reaction and/or transition, the onset temperature and extrapolated onset temperature o f the first reaction or transition (bearing in mind that, very o ften, these onset temperatures are poorly defined in the case o f polymers having an extremely broad melting range o f up to 150 K) and the extrapolated end temperature and end temperature o f the last reaction or transition, as well as several peak temperatures It is not always possible to identi fy all o f these individual reactions and/or transitions by DSC alone In some cases, it may be help ful to adjust the heating and/or cooling rates to enhance the separation o f these phenomena However, care should be exercised as the heating and cooling rates can have a significant e ffect on the characteristic temperature(s) observed at the subsequent heating or cooling rate For some polymers, the DSC curve can have several peaks during the first heating run while there is only one peak during the second heating run Normally, a cooling run per formed at the same rate (e.g 10 K/min or 20 K/min) as that used for heating precedes the second heating scan The information obtained in the first heating run may be indicative o f the thermal history o f the polymer (such as processing and specimen conditioning and preparation) There fore, it is advisable when analysing polymers to carry out three DSC runs: first heating, then cooling and finally second heating, pre ferably at the same rate Using this procedure in conjunction with a record o f the initial mass o f the specimen in the crucible and the masses of the specimen in the crucible before and after the second heating scan can aid identification o f the various peaks observed To obtain in formation on the thermal properties o f the sample material without being influenced by its thermal history, the results o f the cooling and second heating scan should be used With respect to the solid-liquid phase transition, this means that the cooling run will indicate nucleation and the temperature or kinetics o f crystallization while the second heating will reflect the material-specific melting properties o f the polymer O f course, the glass transition characteristics can be estimated as well without being perturbed by thermal history In the event of gas evolution (due to decomposition, solvent evaporation, etc.) during the heating of a specimen, the pressure generated inside a hermetically sealed crucible can de form the crucible This results in disturbance o f the heat trans fer between the specimen and the measuring system To avoid such disturbances, a punched (perforated) lid or a special pressure-tight crucible can be used © ISO 2016 – All rights reserved 31 ISO 113 57-1:2 016(E) To i nve s tigate chem ica l re ac tion s instruments are available 32 i nduce d by exp o s u re to vi s ible or UV l ight, s p e c ia l to -D S C © ISO 2016 – All rights reserved ISO 1 7-1 : 01 6(E) Bibliography [1] [2] [3] [7] ISO 291, Plastics — Standard atmospheres for conditioning and testing H ill J.O ed For better thermal analysis and calorimetry ICTA, Third Edition, 1991 P re s ton-T hom as H The International Temperature Scale of 1990 (ITS-90) Metrologia 1990, p C ammenga H.K Temperature, heat and heat flow rate calibration of di fferential scanning calorimeters Thermochim Acta 1993, p 333 S arge S.M The caloric calibration of scanning calorimeters Thermochim Acta 1994, p 129 S arge S.M Metrologically based procedures for the temperature, heat and heat flow rate calibration o f DSC J Therm Anal 1997, p 1125 Wunderlich B Thermal analysis Academic Press, London, 1990 [8] M athot V.F.B ed Calorimetry and thermal analysis o f polymers Hanser/Gardner, Cincinnati, 27 [4] 219 [5] [6] 47 49 [9] [10] [11] [12] Ohio, 1994 Höhne G.W.H Di fferential scanning calorimetry: An introduction for practitioners Springer, Berlin, 1996 T uri E.A ed Thermal characterization of polymeric materials Academic Press, New York, 1997 C all anan J.E NBS Spec Publ 260-99 (1985) S ch ubnell M Temperature and heat flow calibration of a DSC-instrument in the temperature range between -100 and 160°C T Therm Anal Cal 2000, p 91 Höhne G.W.H The temperature calibration of scanning calorimeters Thermochim Acta 1990, p 25 61 [13] 160 © ISO 2016 – All rights reserved 33 ISO 113 57-1:2 016(E) ICS 83.080.01 Price based on 33 pages © ISO 2016 – All rights reserved