SIST EN ISO 11357-1:2023
(Main)Plastics - Differential scanning calorimetry (DSC) - Part 1: General principles (ISO 11357-1:2023)
Plastics - Differential scanning calorimetry (DSC) - Part 1: General principles (ISO 11357-1:2023)
The ISO 11357 series specifies several differential scanning calorimetry (DSC) methods for the thermal analysis of polymers and polymer blends, such as
— thermoplastics (polymers, moulding compounds and other moulding materials, with or without fillers, fibres or reinforcements),
— thermosets (uncured or cured materials, with or without fillers, fibres or reinforcements), and
— elastomers (with or without fillers, fibres or reinforcements).
The ISO 11357 series is applicable for the observation and measurement of various properties of, and phenomena associated with, the above-mentioned materials, such as
— physical transitions (glass transition, phase transitions such as melting and crystallization, polymorphic transitions, etc.),
— chemical reactions (polymerization, crosslinking and curing of elastomers and thermosets, etc.),
— the stability to oxidation, and
— the heat capacity.
This document specifies a number of general aspects of differential scanning calorimetry, such as the principle and the apparatus, sampling, calibration and general aspects of the procedure and test report common to all parts.
Details on performing specific methods are given in subsequent parts of the ISO 11357 series (see Foreword).
Kunststoffe - Dynamische Differenzkalorimetrie (DSC) - Teil 1: Allgemeine Grundlagen (ISO 11357-1:2023)
Die Normenreihe ISO 11357 legt verschiedene Verfahren der Dynamische Differenzkalorimetrie (en: differential scanning calorimetry, DSC) zur thermischen Analyse von Polymeren und Polymermischungen fest, wie z. B. von
Thermoplasten (Polymeren, Formmassen und Produkten des Formpressens mit oder ohne Füllstoffe, Fasern oder Verstärkungsstoffe),
Duroplasten (gehärteten oder ungehärteten Materialien mit oder ohne Füllstoffe, Fasern oder Verstärkungsstoffe) und
Elastomeren (mit oder ohne Füllstoffe, Fasern oder Verstärkungsstoffe).
Die Normenreihe ISO 11357 wird zwecks Beobachtung und quantitativer Erfassung verschiedener Erscheinungen oder Eigenschaften der oben genannten Materialien angewendet, wie z. B.
physikalischer Umwandlungen (Glasübergang, Phasenumwandlungen wie Schmelzen oder Kristallisation, polymorphen Umwandlungen usw.),
chemischer Reaktionen (Polymerisation, Vernetzung und Vulkanisation von Elastomeren und Duroplasten usw.),
Oxidationsstabilität und
Wärmekapazität.
Dieses Dokument legt eine Reihe allgemeiner Grundsätze der Dynamischen Differenzkalorimetrie fest, wie z. B. Kurzbeschreibung des Verfahrens und der Geräte, Probenahme, Kalibrierung sowie allgemeine Aspekte des Verfahrens und des Prüfberichts, die allen Teilen gemeinsam sind.
Einzelheiten zur Durchführung spezifischer Verfahren sind in den nachfolgenden Teilen der Normenreihe ISO 11357 (siehe Vorwort) angegeben.
SICHERHEITSHINWEIS — Personen, die dieses Dokument anwenden, sollten mit der üblichen Laborpraxis vertraut sein, soweit gegeben. Das vorliegende Dokument beabsichtigt nicht, alle mit dessen Anwendung verbundenen Sicherheitsprobleme, soweit sich solche ergeben, anzusprechen. Es liegt in der Verantwortung des Anwenders, angemessene Maßnahmen in Bezug auf den Gesundheits- und Arbeitsschutz einzuleiten und anwendbare regulatorische Anforderungen zu bestimmen.
Plastiques - Analyse calorimétrique différentielle (DSC) - Partie 1: Principes généraux (ISO 11357-1:2023)
La série ISO 11357 spécifie plusieurs méthodes d’analyse calorimétrique différentielle (DSC) pour l’analyse thermique des polymères et des mélanges de polymères tels que:
— thermoplastiques (polymères, composants pour moulage et autres produits pour moulage avec ou sans charge(s), fibres ou additifs de renforcement),
— thermodurcissables (matériaux non durcis ou durcis, avec ou sans charge(s), fibres ou additifs de renforcement), et
— élastomères (avec ou sans charge(s), fibres ou additifs de renforcement).
La série ISO 11357 s’applique pour l’observation et le mesurage de différentes propriétés ou phénomènes associés des matériaux susmentionnés tels que:
— les transitions physiques (transition vitreuse, transitions de phases telles que la fusion et la cristallisation, les transitions polymorphes, etc.),
— les réactions chimiques (polymérisation, réticulation et durcissement des élastomères et des thermodurcissables, etc.),
— la stabilité à l’oxydation, et
— la capacité thermique.
Le présent document spécifie plusieurs aspects généraux de l’analyse calorimétrique différentielle, tels que le principe et l’appareillage, l’échantillonnage, l’étalonnage et les aspects généraux du mode opératoire et du rapport d’essai communs à toutes les parties.
Les détails relatifs à la réalisation des méthodes spécifiques sont donnés dans les autres parties de la série ISO 11357 (voir l’Avant-propos).
Polimerni materiali - Diferenčna dinamična kalorimetrija (DSC) - 1. del: Splošna načela (ISO 11357-1:2023)
Standard ISO 11357-1:2016 določa različne metode diferenčne dinamične kalorimetrije (DSC) za toplotno analizo polimerov in mešanic polimerov, kot so:
– plastomeri (polimeri, zmesi za oblikovanje in drug material za oblikovanje, s polnili, vlakni in ojačitvami ali brez njih),
– termoreaktivni materiali (nestrjeni ali strjeni materiali s polnili, vlakni in ojačitvami ali brez njih) in
– elastomeri (s polnili, vlakni in ojačitvami ali brez njih).
Standard ISO 11357-1:2016 je namenjen opazovanju in merjenju različnih lastnosti (in z njimi povezanih pojavov) zgoraj omenjenih materialov, kot so:
– fizične prehodnosti (prehodnost stekla, prehodna stanja, kot sta topljenje in kristalizacija, polimorfna prehodnost, itd.),
– kemične reakcije (polimerizacija, prečno povezovanje in strjevanje elastomerov in termoreaktivnih materialov itd.),
– odpornost proti oksidaciji in
– toplotna kapaciteta.
Standard ISO 11357-1:2016 določa število splošnih lastnosti diferenčne dinamične kalorimetrije, kot so načelo in aparat, vzorčenje, kalibracija splošnih lastnosti postopka in poročila o preskušanju, skupna vsem naslednjim delom.
Podrobnosti o izvajanju določenih metod so podane v naslednjih delih standarda ISO 11357 (glej predgovor).
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2023
Polimerni materiali - Diferenčna dinamična kalorimetrija (DSC) - 1. del: Splošna
načela (ISO 11357-1:2023)
Plastics - Differential scanning calorimetry (DSC) - Part 1: General principles (ISO 11357
-1:2023)
Kunststoffe - Dynamische Differenzkalorimetrie (DSC) - Teil 1: Allgemeine Grundlagen
(ISO 11357-1:2023)
Plastiques - Analyse calorimétrique différentielle (DSC) - Partie 1: Principes généraux
(ISO 11357-1:2023)
Ta slovenski standard je istoveten z: EN ISO 11357-1:2023
ICS:
17.200.10 Toplota. Kalorimetrija Heat. Calorimetry
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 11357-1
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2023
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 11357-1:2016
English Version
Plastics - Differential scanning calorimetry (DSC) - Part 1:
General principles (ISO 11357-1:2023)
Plastiques - Analyse calorimétrique différentielle (DSC) Kunststoffe - Dynamische Differenzkalorimetrie (DSC)
- Partie 1: Principes généraux (ISO 11357-1:2023) - Teil 1: Allgemeine Grundlagen (ISO 11357-1:2023)
This European Standard was approved by CEN on 25 February 2023.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11357-1:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 11357-1:2023) has been prepared by Technical Committee ISO/TC 61 "Plastics"
in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by
NBN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2023, and conflicting national standards
shall be withdrawn at the latest by September 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11357-1:2016.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 11357-1:2023 has been approved by CEN as EN ISO 11357-1:2023 without any
modification.
INTERNATIONAL ISO
STANDARD 11357-1
Fourth edition
2023-02
Plastics — Differential scanning
calorimetry (DSC) —
Part 1:
General principles
Plastiques — Analyse calorimétrique différentielle (DSC) —
Partie 1: Principes généraux
Reference number
ISO 11357-1:2023(E)
ISO 11357-1:2023(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of 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 of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 11357-1:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Basic principles . 8
4.1 General . 8
4.2 Heat-flux DSC . 8
4.3 Power-compensation DSC . 8
5 Apparatus and materials .9
6 Specimen .10
7 Test conditions and specimen conditioning .11
7.1 Test conditions . 11
7.2 Conditioning of specimens . 11
8 Calibration .11
8.1 General . 11
8.2 Calibration materials .12
8.3 Temperature calibration .12
8.3.1 General .12
8.3.2 Procedure .12
8.3.3 Accuracy of calibration . 13
8.4 Heat calibration . 13
8.4.1 General .13
8.4.2 Procedure . 14
8.4.3 Accuracy of calibration . 14
8.5 Heat flow rate calibration . 14
8.5.1 General . 14
8.5.2 Procedure . 15
9 Procedure .17
9.1 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
9.2 Loading the specimen into the crucible . 17
9.2.1 General . 17
9.2.2 Selection of crucibles . 17
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
9.3 Insertion of crucibles into the instrument . 18
9.4 Performing measurements . 18
9.4.1 General . 18
9.4.2 Scanning mode . 18
9.4.3 Isothermal mode . 19
9.5 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
10 Test report .20
iii
ISO 11357-1:2023(E)
[12]
Annex A (normative) Extended, high-precision, temperature calibration .22
Annex B (normative) Extended, high-precision, heat calibration .24
Annex C (informative) Recommended calibration materials .26
Annex D (informative) Interaction of calibration materials with different crucible materials .30
Annex E (informative) General recommendations .32
Bibliography .34
iv
ISO 11357-1:2023(E)
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 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 of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of 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 information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-
chemical properties., in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation between
ISO and CEN (Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 11357-1:2016), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the examples of materials given for temperature and enthalpy calibration have been updated;
— the data of sapphire to be used for calibration of heat flow rate have been updated.
A list of all parts in the ISO 11357 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
ISO 11357-1:2023(E)
Introduction
The ISO 11357 series describes thermoanalytical DSC test methods which can be used for quality
assurance purposes, for routine checks of raw materials and finished products, or for the determination
of comparable data needed for data sheets or databases. The procedures given in ISO 11357 apply as
long as product standards or standards describing special atmospheres for conditioning of specimens
do not specify otherwise.
vi
INTERNATIONAL STANDARD ISO 11357-1:2023(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 determine applicable regulatory requirements.
1 Scope
The ISO 11357 series specifies several differential scanning calorimetry (DSC) methods for the thermal
analysis of polymers and polymer blends, such as
— thermoplastics (polymers, moulding compounds and other moulding materials, with or without
fillers, fibres or reinforcements),
— thermosets (uncured or cured materials, with or without fillers, fibres or reinforcements), and
— elastomers (with or without fillers, fibres or reinforcements).
The ISO 11357 series is applicable for the observation and measurement of various properties of, and
phenomena associated with, the above-mentioned materials, such as
— physical transitions (glass transition, phase transitions such as melting and crystallization,
polymorphic transitions, etc.),
— chemical reactions (polymerization, crosslinking and curing of elastomers and thermosets, etc.),
— the stability to oxidation, and
— the heat capacity.
This document specifies a number of general aspects of differential scanning calorimetry, such as the
principle and the apparatus, sampling, calibration and general aspects of the procedure and test report
common to all parts.
Details on performing specific methods are given in subsequent parts of the ISO 11357 series (see
Foreword).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 472, Plastics — Vocabulary
ISO 80000-5, Quantities and units — Part 5: Thermodynamics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472, ISO 80000-5 and the
following apply.
ISO 11357-1:2023(E)
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
differential scanning calorimetry
DSC
technique in which the difference between the rate of flow of heat into a specimen crucible containing
the specimen and that into a reference crucible (3.3) is derived as a function of temperature and/or time
while the specimen and reference are subjected to the same controlled temperature programme in a
specified atmosphere using a symmetrical measurement system
Note 1 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 2 to entry: According to the principles of 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 1 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 of the thermal properties are sufficiently 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 reference side of the symmetrical crucible holder assembly
Note 1 to entry: Normally, the reference crucible is empty.
Note 2 to entry: In special cases, such as the measurement of highly filled or reinforced polymers or specimens
having a heat capacity comparable to that of the crucible, a suitable material can be used inside the reference
crucible. Suitable reference materials are thermally inactive over the temperature and time range of interest and
have heat capacities similar to that of the specimen. In the case of filled or reinforced products, the pure filler or
reinforcement can be used, for example.
3.4
heat flow rate
quantity of heat transferred per unit time (dQ/dt)
Note 1 to entry: It is expressed in watts (W) or milliwatts (mW).
Note 2 to entry: The total quantity of heat transferred, Q, corresponds to the time integral of the heat flow rate:
dQ
Q =∫ dt
dt
3.5
change in heat
ΔQ
quantity of heat absorbed (endothermic, ΔQ positive) or released (exothermic, ΔQ negative) within a
specified time, t, or temperature, T, range by a specimen undergoing a chemical or physical change and/
or a temperature change:
t
2 dQ
ΔQ= dt
∫
t
dt
ISO 11357-1:2023(E)
or
T
60 2 dQ
ΔQ= dT
∫
T
β dt
where
ΔQ is expressed in joules (J) or as a specific quantity, Δq, expressed in joules per amount of material
−1 −1
in grams (J⋅g ) or joules per amount of material in moles (J⋅mol );
−1
β is the constant heating or cooling rate, dT/dt, expressed in kelvins per minute (K⋅min ).
Note 1 to entry: If measurements are made at constant pressure, ΔQ corresponds to the change in enthalpy, ΔH.
3.6
specific heat capacity at constant pressure
c
p
quantity of heat necessary to raise the temperature of unit mass of material by 1 K at constant pressure:
1dQ
c =×
p
m dT
p
or
160 dQ
c =× ×
p
m β dt
p
where
dQ is the quantity of heat, expressed in joules (J), necessary to raise the temperature of an amount
of material of mass m, expressed in grams (g), by dT kelvins at constant pressure;
−1
β is the heating rate, expressed in kelvins per minute (K⋅min );
−1 −1
c is expressed in joules per gram per kelvin (J⋅g ⋅K ).
p
−1 −1
Note 1 to entry: c can also be expressed in joules per mole per kelvin (J⋅mol ⋅K ) when the amount of material,
p
m, is expressed in moles.
Note 2 to entry: When analysing polymers, ensure that the measured specific heat capacity does not include any
heat change due to a chemical reaction or a physical transition.
3.7
baseline
part of the recorded curve in which no reactions or transitions take place
Note 1 to entry: This can be an isothermal baseline when the temperature is maintained constant or a dynamic
baseline when the temperature is changed in accordance with a controlled temperature programme.
Note 2 to entry: The baselines defined in 3.7.1 to 3.7.3 refer to the quasi-stationary range only, i.e. when the
instrument is operating under stable conditions shortly after starting and shortly before ending the DSC run (see
Figure 1).
ISO 11357-1:2023(E)
Key
dQ/dt heat flow rate 2 virtual baseline
T temperature 3 instrument baseline
t time 4 quasi-stationary range
dQ/dt vs. t 5 isothermal start baseline
T vs. t 6 isothermal end baseline
a
1 specimen baselines Endothermic direction.
Figure 1 — Schematic drawing showing baselines
3.7.1
instrument baseline
curve obtained using only empty crucibles of identical mass and material in the specimen and reference
positions of the DSC cell
Note 1 to entry: The instrument baseline is required for heat capacity measurements.
3.7.2
specimen baseline
DSC curve obtained outside any reaction or transition zone(s) while the instrument is loaded with both
the specimen in the specimen crucible and the reference crucible (3.3)
Note 1 to entry: In this part of the curve, the difference in heat flow rate (3.4) between the specimen crucible and
the reference crucible (3.3) depends solely on the heat capacity of the specimen and the instrument baseline (3.7.1).
Note 2 to entry: The specimen baseline reflects the temperature dependence of the heat capacity of the specimen.
Note 3 to entry: For heat capacity determinations, a dynamic DSC curve is required and, in addition, the
instrument baseline (3.7.1) and the isothermal start and end baselines (see Figure 1).
ISO 11357-1:2023(E)
3.7.3
virtual baseline
imaginary line drawn along the peak width through a reaction and/or transition zone assuming the
heat of reaction and/or transition to be zero
Note 1 to entry: Assuming the change in heat capacity with temperature to be linear, the virtual baseline is
drawn by interpolating or extrapolating the specimen baseline in a straight line. It is normally indicated on the
DSC curve for convenience (see Figures 1 and 2).
Note 2 to entry: The virtual baseline drawn from peak onset, T , to peak end, T , i.e., the peak baseline, (see
i f
Figure 2) allows the determination of the peak area from which the heat of transition can be obtained. If there
is no significant change in heat capacity during the transition or reaction, the baseline can be drawn simply by
connecting the peak onset and peak end by a straight line. If significant heat capacity changes occur, a sigmoidal
baseline can be drawn.
Note 3 to entry: Extrapolated and interpolated virtual baselines will not necessarily coincide with each other
(see Figure 2).
3.8
step
abrupt positive or negative change in the height of a DSC curve, taking place over a limited temperature
range
Note 1 to entry: A step in the DSC curve can be caused by, for example, a glass transition (see Figure 2).
3.8.1
step height
difference between the heights of the extrapolated baselines before and after a step, measured at the
time or temperature corresponding to the point on the DSC curve which is equidistant between the two
baselines
3.9
peak
part of the DSC curve which departs from the specimen baseline (3.7.2), reaches a maximum or minimum,
and subsequently returns to the specimen baseline (3.7.2)
Note 1 to entry: A peak in the DSC curve can indicate a chemical reaction or a first-order transition. The initial
departure of the peak from the virtual baseline (3.7.3) corresponds to the start of the reaction or transition.
3.9.1
endothermic peak
peak in which the rate of flow of heat into the specimen crucible is greater than that into the reference
crucible (3.3)
Note 1 to entry: This corresponds to a transition which absorbs heat.
3.9.2
exothermic peak
peak in which the rate of flow of heat into the specimen crucible is less than that into the reference
crucible (3.3)
Note 1 to entry: This corresponds to a transition which releases heat.
3.9.3
peak area
area enclosed by a peak and the interpolated virtual baseline (3.7.3)
ISO 11357-1:2023(E)
3.9.4
peak height
greatest distance in the ordinate direction between the interpolated virtual baseline (3.7.3) and the DSC
curve during a peak
Note 1 to entry: The peak height, which is expressed in watts (W) or watts per gram (W/g) with optional use of
any SI prefix, is not necessarily proportional to the mass of the specimen.
3.9.5
peak width
distance between the onset and end temperatures or times of a peak
3.10
characteristic temperatures, T, and times, t
values for temperature and time obtained from the DSC curve
Note 1 to entry: See Figure 2.
Note 2 to entry: For all types of DSC instrument, a distinction needs to be made between two different categories
of temperature:
— the temperature at the reference position;
— the temperature at the specimen position.
The reference position temperature is the one preferred for plotting thermograms. If the specimen position
temperature is used, then this information will need to be included in the test report.
Note 3 to entry: Characteristic temperatures are expressed in degrees Celsius (°C), relative temperatures and
temperature differences in kelvins (K) and characteristic times in seconds (s) or minutes (min) (see Figure 2).
Note 4 to entry: The DSC curve can also be plotted using time, t, as the abscissa instead of temperature, T.
ISO 11357-1:2023(E)
Key
dQ/dt heat flow rate extrapolated baseline
T temperature (or t, time) interpolated baseline
Characteristic temperatures if temperature is used as abscissa scale (similarly, characteristic times apply
if time is used as abscissa scale)
The first subscript, or pair of subscripts, denotes the position on the DSC curve with respect to the step or peak:
— onset temperature T first detectable departure of curve from
i
extrapolated start baseline;
— interpolated or extrapolated onset temperature T (for a peak) point of intersection of
ei
interpolated virtual baseline and tangent
drawn at point of inflection of near side of
peak or (for a step) point of intersection
of extrapolated start baseline and tangent
drawn at point of inflection of step;
— midpoint temperature T half of the step height;
1/2
— peak temperature T greatest distance between curve and
p
virtual baseline during an endothermic or
exothermic peak, i.e., peak height;
— interpolated or extrapolated end temperature T (for a peak) point of intersection of
ef
interpolated virtual baseline and tangent
drawn at point of inflection of far side of
peak or (for a step) point of intersection
of extrapolated end baseline and tangent
drawn at point of inflection of step;
— end temperature T last detectable deviation of curve from
f
extrapolated end baseline.
The second subscript indicates the type of transition:
g glass transition
c crystallization
m melting
a
Endothermic direction.
Figure 2 — Typical DSC curve (schematic)
ISO 11357-1:2023(E)
4 Basic principles
4.1 General
The difference between the rate of heat flow into a specimen and that into a reference crucible is
measured as a function of temperature and/or time while the specimen and the reference are subjected
to the same temperature-control programme under a specified atmosphere.
Two types of DSC can be carried out: heat-flux DSC and power-compensation DSC.
4.2 Heat-flux DSC
The specimen and reference positions are subjected to the same temperature-control programme by a
single heater. A difference in temperature, ΔT, occurs between the specimen position and the reference
position because of the difference in heat capacity between the specimen and the reference. From
this temperature difference, the difference in the rates of heat flow into the specimen and reference
positions is derived and is normally recorded against the temperature of the reference, T , or against
ref
time.
A schematic drawing of a heat-flux DSC instrument is shown in Figure 3.
Key
1 specimen position 6 surrounding oven
2 reference position T temperature at specimen position (T )
1 s
3 thermocouples T temperature at reference position (T )
2 ref
4 single heater ΔT temperature difference between specimen and
reference positions
5 measurement circuit for T , T and ΔT
s ref
Figure 3 — Schematic diagram illustrating the basic principles of heat-flux DSC
4.3 Power-compensation DSC
In power-compensated DSC, individual heaters are used for the specimen and reference positions.
The difference in electrical power required to maintain both the specimen position and the reference
position at the same temperature is recorded against temperature or time, while each position is
subjected to the same temperature-control programme.
For power-compensated isoperibolic calorimeters, the surrounding temperature (i.e. the temperature
of the heat sink) has to be kept constant.
A schematic drawing of a power-compensation DSC instrument is shown in Figure 4.
ISO 11357-1:2023(E)
Key
1 specimen position T temperature at specimen position (T )
1 s
2 reference position T temperature at reference position (T )
2 ref
3 thermometers
4 individual heaters
5 measurement circuit for T and T
s ref
6 power compensation circuit
7 surrounding heat sink
Figure 4 — Schematic diagram illustrating the basic principles of power-compensation DSC
5 Apparatus and materials
5.1 Differential scanning calorimeter, with the following features:
a) A symmetrical crucible holder assembly which has holders for the specimen and reference
crucibles.
b) The capability to generate constant heating and cooling rates suitable for the intended
measurements.
c) The capability to maintain the test temperature constant to within ±0,3 K or less for at least 60 min.
d) The capability to carry out step heating or step cooling.
NOTE 1 Normally, this is achieved by a suitable combination of linear heating or cooling and constant-
temperature regimes.
e) The capability to maintain a constant purge gas flow rate controllable to within ±10 % over a range
−1 −1
of flow rates (e.g., 10 ml⋅min to 100 ml⋅min ).
NOTE 2 The actual gas flow rate depends on the design of the instrument used.
f) A temperature range in line with the experimental requirements.
g) A heat flow rate range of ±100 mW or more.
h) A recording device capable of automatically recording the measured curve of heat flow rate against
temperature and time.
i) The capability to measure temperature signals with a resolution of ±0,1 K and an accuracy of ±0,5 K
or better.
j) The capability to measure time with a resolution of ±0,5 s and an accuracy of ±1 s or better.
k) The capability to measure heat flow rates with a resolution of ±0,5 µW and an accuracy of ±2 µW or
better.
ISO 11357-1:2023(E)
5.2 Crucibles, for the specimen and reference positions. They shall be of the same type, made of the
same material and have similar masses. They shall be physically and chemically inert to the specimen,
the calibration materials and the purge gas under the measurement conditions (see Annexes C and D).
NOTE 1 If required, small variations of crucible mass can be arithmetically corrected for, if the specific heat
capacity of the crucible material is known.
Crucibles should preferably be made of a material with a high thermal conductivity, e.g. aluminium.
Ventilated crucibles should preferably be used to avoid changes in pressure during the measurement
run and to allow the exchange of gas with the surrounding atmosphere. However, for special purposes,
crucibles closed with lids or hermetically sealed crucibles can be required so that they will withstand
the overpressure arising during the measurement run.
When using special high-pressure or glass crucibles, their relatively high mass and poor thermal
conductivity shall be taken into account. Recalibration of the instrument can be required.
NOTE 2 When using high-pressure or hermetically closed crucibles, measurements are not necessarily
performed at constant pressure. Hence, the constant-pressure requirement for measuring enthalpies or c are
p
not necessarily fulfilled.
5.3 Balance, capable of measuring the specimen mass with a resolution of ±0,01 mg and an accuracy
of ±0,1 mg or better.
5.4 Calibration materials, covering the temperature range of interest and preferably chosen from
the list of recommended calibration materials in Annex C.
5.5 Purge gas, preferably a dry and inert gas (e.g. nitrogen of purity 99,99 % or better), used to avoid
oxidative or hydrolytic degradation during testing.
For the investigation of chemical reactions, including oxidation, special reactant gases may be required.
If a gas generator is used to supply gas for purging and environmental control during testing, rather
than using a pressurized gas bottle purge, it is recommended that suitable drying and filtering systems
be installed.
6 Specimen
The specimen shall be in the liquid or solid state. Solid-state specimens may be in any form which fits
into the crucible (e.g. powder, pellets, granules, fibres) or may be cut from bigger pieces to a suitable size.
The specimen shall be representative of the sample being examined and shall be prepared and handled
with care. Particular care shall be taken to avoid any contamination of the specimen. If the specimen is
taken from larger pieces by cutting, care shall be taken to prevent heating, polymer orientation or any
other effect that can alter the specimen properties. Operations, such as grinding, that can cause heating
or reorientation and can therefore change the thermal history of the specimen shall be avoided. The
method of sampling and specimen preparation shall be stated in the test report.
If the specimen crucible is closed or sealed with a lid, this shall not cause any deformation of the bottom
of the crucible. Good thermal contact between the specimen and crucible and between the crucible and
holder shall be ensured.
Typical specimen masses are between 2 mg and 40 mg.
NOTE Incorrect specimen preparation can change the thermal properties of the polymers examined. For
further information, refer to Annex E.
ISO 11357-1:2023(E)
7 Test conditions and specimen conditioning
7.1 Test conditions
The instrument shall be maintained and operated in an atmosphere suitable for the intended test.
Unless excluded by special requirements for particular test procedures, all calibration and test
measurements shall be performed using closed, ventilated crucibles, preferably made of aluminium, to
improve reproducibility.
It is recommended that the instrument be protected from air draughts, exposure to direct sunlight and
abrupt changes in temperature, pressure or mains voltage.
7.2 Conditioning of specimens
Specimens shall be conditioned prior to the measurement run as specified in the relevant material
standard or by a method agreed between the interested parties.
Unless otherwise specified, specimens shall be dried to constant mass before performing measurements.
Care shall be taken to choose suitable drying conditions to prevent physical changes, such as ageing or
changes in crystallinity of the specimens.
NOTE Depending on the material and its thermal history, the methods of preparation and conditioning of the
sample and specimens can be crucial to the values obtained, the consistency of the results and their significance.
8 Calibration
8.1 General
Before commissioning a new instrument or after replacing or modifying essential components or after
cleaning the measuring cell by heating to elevated temperatures, the calorimeter shall be calibrated
at least with respect to temperature and heat. In addition, heat flow rate calibration can be required
for heat capacity measurements. Recalibration of the instrument shall be carried out regularly at the
required calibration intervals, e.g. when the instrument is being used as part of a quality assurance
system.
NOTE In many cases, the calibration procedures are built into the instrument control software and thus at
least partly automated.
Recalibration of the instrument should preferably be performed each time the test conditions are
significantly changed. More frequent checks may be carried out as required.
The calibration can be affected by the following:
— type of calorimeter used and its stability;
— heating and cooling rates;
— type of cooling system used;
— type of purge gas used and its flow rate;
— type of crucible used, the crucible size and the positions of the crucibles in the crucible holde
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