EN ISO 11357-1:2009

SLOVENSKI STANDARD
01-januar-2010
1DGRPHãþD
SIST EN ISO 11357-1:1999
3ROLPHUQLPDWHULDOL'LIHUHQþQDGLQDPLþQDNDORULPHWULMD'6&GHO6SORãQD
QDþHOD,62
Plastics - Differential scanning calorimetry (DSC) - Part 1: General principles (ISO 11357
-1:2009)
Kunststoffe - Dynamische Differenz-Thermoanalyse (DSC) - Teil 1: Allgemeine
Grundlagen (ISO 11357-1:2009)
Plastiques - Analyse calorimétrique différentielle (DSC) - Partie 1: Principes généraux
(ISO 11357-1:2009)
Ta slovenski standard je istoveten z: EN ISO 11357-1:2009
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.

EUROPEAN STANDARD
EN ISO 11357-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2009
ICS 83.080.01 Supersedes EN ISO 11357-1:1997
English Version
Plastics - Differential scanning calorimetry (DSC) - Part 1:
General principles (ISO 11357-1:2009)
Plastiques - Analyse calorimétrique différentielle (DSC) - Kunststoffe - Dynamische Differenz-Thermoanalyse (DSC)
Partie 1: Principes généraux (ISO 11357-1:2009) - Teil 1: Allgemeine Grundlagen (ISO 11357-1:2009)
This European Standard was approved by CEN on 17 September 2009.

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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11357-1:2009: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 11357-1:2009) 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 April 2010, and conflicting national standards shall be withdrawn at the
latest by April 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11357-1:1997.
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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 11357-1:2009 has been approved by CEN as a EN ISO 11357-1:2009 without any
modification.
INTERNATIONAL ISO
STANDARD 11357-1
Second edition
2009-10-15
Plastics — Differential scanning
calorimetry (DSC) —
Part 1:
General principles
Plastiques — Analyse calorimétrique différentielle (DSC) —
Partie 1: Principes généraux
Reference number
ISO 11357-1:2009(E)
©
ISO 2009
ISO 11357-1:2009(E)
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ii © ISO 2009 – All rights reserved

ISO 11357-1:2009(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
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
8.4 Heat calibration.14
8.5 Heat flow rate calibration.15
9 Procedure.17
9.1 Setting up the apparatus .17
9.2 Loading the specimen into the crucible.17
9.3 Insertion of crucibles into the instrument .18
9.4 Performing measurements.18
9.5 Post-run checks.20
10 Test report.21
[11]
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 .29
Annex E (informative) General recommendations.30
Bibliography.31

ISO 11357-1:2009(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11357-1 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-
chemical properties.
This second edition cancels and replaces the first edition (ISO 11357-1:1997), which has been technically
revised. The most important changes are the following:
⎯ an indication has been given of the preferred graphical representation of DSC diagrams in accordance
with thermodynamic requirements;
⎯ an additional, more precise, method of temperature calibration, providing an accuracy of ± 0,3 K over an
extended temperature range, has been included;
⎯ an additional, more precise, procedure for enthalpy calibration, providing an accuracy of ± 0,5 %, has
been included;
⎯ a procedure for heat flow rate calibration has been included;
⎯ information has been included on interactions between calibration materials and the crucibles.
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
⎯ 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 of oxidation induction time (isothermal OIT) and oxidation induction temperature
(dynamic OIT)
⎯ Part 7: Determination of crystallization kinetics
iv © ISO 2009 – All rights reserved

ISO 11357-1:2009(E)
Introduction
ISO 11357 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.

INTERNATIONAL STANDARD ISO 11357-1:2009(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.
1 Scope
ISO 11357 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);
⎯ elastomers (with or without fillers, fibres or reinforcements).
ISO 11357 is intended 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;
⎯ the heat capacity.
This part of ISO 11357 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 following parts.
Details on performing specific methods are given in subsequent parts of ISO 11357 (see Foreword).
2 Normative references
The following referenced documents are indispensable for the application 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 291, Plastics — Standard atmospheres for conditioning and testing
ISO 11357-1:2009(E)
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 and ISO 80000-5 and the
following apply.
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 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 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 difference as the ordinate. The endothermic and/or exothermic direction is indicated on the
DSC curve.
NOTE 2 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 and specific heat are 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 Normally the reference crucible is empty.
NOTE 2 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. This reference
material should be thermally inactive over the temperature and time range of interest and its heat capacity should be
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), expressed in watts (W) or milliwatts (mW)
NOTE The total quantity of heat transferred, Q, corresponds to the time integral of the heat flow rate:
dQ
Qt= d (1)
∫
dt
2 © ISO 2009 – All rights reserved

ISO 11357-1:2009(E)
3.5
change in heat
∆Q
quantity of heat absorbed (endothermic, ∆Q positive) or released (exothermic, ∆Q 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
dQ
∆=Qtd (2)
∫
dt
t
or
T
60 dQ
∆=QTd (3)
∫
β dt
T
where
∆Q is expressed in joules (J) or as a specific quantity, ∆q, expressed in joules per amount of material in
−1 −1
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 If measurements are made at constant pressure, ∆Q corresponds to the change in enthalpy, ∆H.
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:
1d⎛⎞Q
c =× (4)
⎜⎟
p
mTd
⎝⎠
p
or
160⎛⎞dQ
c =× × (5)
p ⎜⎟
mtβ d
⎝⎠
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 c may also be expressed in joules per mole per kelvin (J⋅mol ⋅K ) when the amount of material, m, is
p
expressed in moles.
NOTE 2 When analysing polymers, it is necessary to ensure that the measured specific heat capacity does not include
any heat change due to a chemical reaction or a physical transition.
ISO 11357-1:2009(E)
3.7
baseline
that part of the recorded curve in which no reactions or transitions take place
NOTE 1 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 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).

Key
dQ/dt heat flow rate 3 specimen baselines
T temperature 4 virtual baseline
t time 5 instrument baseline
1 dQ/dt vs t (or T) 6 quasi-stationary range
2 T vs t 7 isothermal start baseline
8 isothermal end baseline
a
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 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
NOTE 1 In this part of the curve, the difference in heat flow rate between the specimen crucible and the reference
crucible depends solely on the heat capacity of the specimen and the instrument baseline.
4 © ISO 2009 – All rights reserved

ISO 11357-1:2009(E)
NOTE 2 The specimen baseline reflects the relatively low temperature dependence of the heat capacity of the
specimen and is thus approximately constant, i.e. the baseline is approximately flat.
NOTE 3 For heat capacity determinations, a dynamic DSC curve is required and, in addition, the instrument baseline
and the isothermal start and end baselines (see Figure 1).
3.7.3
virtual baseline
imaginary line drawn through a reaction and/or transition zone assuming the heat of reaction and/or transition
to be zero
NOTE 1 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 The virtual baseline drawn from peak onset, T , to peak end, T , (the peak baseline) allows the determination of
i f
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 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 A step in the DSC curve can be caused by e.g. 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, reaches a maximum or minimum, and
subsequently returns to the specimen baseline
NOTE A peak in the DSC curve may indicate a chemical reaction or a first-order transition. The initial departure of the
peak from the virtual baseline 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
NOTE 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
NOTE This corresponds to a transition which releases heat.
3.9.3
peak area
area enclosed by a peak and the interpolated virtual baseline
3.9.4
peak height
greatest distance in the ordinate direction between the interpolated virtual baseline and the DSC curve during
a peak
ISO 11357-1:2009(E)
NOTE The peak height, which is expressed in watts (W) or watts per gram (W/g), 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
These are defined in Figure 2, which shows a typical DSC curve.
NOTE 1 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 which is preferred for plotting thermograms. If the specimen position
temperature is used, then this information will need to be included in the test report.
NOTE 2 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 3 The DSC curve can also be plotted using time, t, as the abscissa instead of temperature, T.
6 © ISO 2009 – All rights reserved

ISO 11357-1:2009(E)
Key
dQ/dt heat flow rate 1 extrapolated baseline
T temperature (or t, time) 2 interpolated baseline
Characteristic temperatures
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 extrapolated start
i
baseline;
⎯ interpolated or extrapolated onset temperature T (for a peak) point of intersection of interpolated virtual
ei
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-height of a step;
1/2
⎯ peak temperature T greatest distance between curve and virtual baseline during
p
a peak;
⎯ interpolated or extrapolated end temperature T (for a peak) point of intersection of interpolated virtual
ef
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 extrapolated end
f
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 11357-1:2009(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, ∆T, 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 time.
ref
A schematic drawing of a heat-flux DSC instrument is shown in Figure 3.

Key
1 specimen position 4 single heater
2 reference position 5 measurement circuit for T , T and ∆T
specimen ref
3 thermocouples 6 surrounding oven
T temperature at specimen position (T )
1 specimen
T temperature at reference position (T )
2 ref
∆T temperature difference between specimen and reference positions
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.
8 © ISO 2009 – All rights reserved

ISO 11357-1:2009(E)
A schematic drawing of a power-compensation DSC instrument is shown in Figure 4.

Key
1 specimen position T temperature at specimen position (T )
1 specimen
2 reference position T temperature at reference position (T )
2 ref
3 thermometers
4 individual heaters
5 measurement circuit for T and T
specimen ref
6 heat-flux 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 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 of
−1 −1
flow rates (e.g. 10 ml⋅min to 100 ml⋅min ).
NOTE The actual gas flow rate will depend 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 ± 1 s or better.
ISO 11357-1:2009(E)
k) The capability to measure heat flow rates with a resolution of ± 0,5 µW and an accuracy of ± 2 µW or
better.
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 in crucible mass can be arithmetically corrected for, given the specific heat
capacity of the crucible material.
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 may 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 may 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 may not be fulfilled.
p
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 may alter
the specimen properties. Operations such as grinding that could cause heating or reorientation and could
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.
10 © ISO 2009 – All rights reserved

ISO 11357-1:2009(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 may 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 may 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 will be 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:
⎯ the type of calorimeter used and its stability;
⎯ the heating and cooling rates;
⎯ the type of cooling system used;
⎯ the type of purge gas used and its flow rate;
⎯ the type of crucible used, the crucible size and the positions of the crucibles in the crucible holder;
⎯ the location of the specimen in the specimen crucible;
⎯ the mass and particle size of the specimen;
⎯ the thermal contact between the specimen crucible and the crucible holder.
ISO 11357-1:2009(E)
The conditions of the actual determination should therefore be defined as precisely as possible and the
calibration carried out under these conditions as closely as possible. Computer-controlled DSC instruments
may automatically correct for the effects of some of these sources of error.
The calibration shall be carried out using the same type of crucible, made of the same material, and using the
same purge gas at the same flow rate as will be used for subsequent measurements.
Calibration specimens shall be heated only slightly above their transition temperatures to prevent reactions
between the calibration materials and the crucibles.
Immediately after the measurement run, the specimens should preferably be cooled until the transition back to
the initial state has taken place.
For most practical measurements, it will be sufficient to use the calibration procedures specified in 8.2 to 8.5.
For more accurate calibrations, the procedures specified in Annexes A and B may be used.
8.2 Calibration materials
Preferably, certified reference materials should be used. The true temperature, T , the true heat of transition,
cal
∆Q , and the true specific heat, c , which are used for the calibration shall be those appearing on the
cal p,cal
certificate accompanying the reference material.
If certified values are not available, the values given in Tables C.1, C.2 and C.3 may be used. Additional
calibration materials may be used provided their thermal properties are sufficiently well defined. The
calibration materials shall not interact with the crucibles or purge gas used (see Annex D).
For each calibration, a fresh calibration specimen shall be used. Any coating of oxide on the surface of the
calibration specimen shall be removed, e.g. by freshly cutting the specimen. The position of the specimen in
the crucible should preferably be kept the same to improve the repeatability of the results.
To avoid misleading results or damage to the crucible holder, combinations of calibration and crucible
materials which are not expected to have any influence on the melting point should preferably be used
(see Annex D). Combinations in which the calibration material is expected to dissolve the crucible material
should be avoided.
8.3 Temperature calibration
8.3.1 General
This is the establishment of the relationship between the temperature, T , indicated by the instrument and
meas
the true temperature, T , of the transition of the calibration material. The relation T = T + ∆T is valid,
cal cal meas corr
where ∆T is a temperature correction.
corr
When using calibration materials other than those listed in Annex C, only first-order transitions, e.g. the
melting of pure substances, shall be used for calibration purposes.
NOTE True transition temperatures can be obtained from calibration material certificates, other qualified sources or
the literature.
With the calibration materials listed in Annex C, temperature calibration shall be carried out in the heating
mode only. However, correctly calibrated instruments that give consistent results in the heating mode will not
necessarily give consistent results in the cooling mode because of supercooling of the substance during the
transition in question. The symmetry of the temperature scale in the heating and cooling mode can be
checked with substances that do not supercool, e.g. liquid crystals.
12 © ISO 2009 – All rights reserved

ISO 11357-1:2009(E)
8.3.2 Procedure
The following procedure describes the minimum requirements for carrying out temperature calibration.
Weigh at least two calibration materials, covering the temperature range required, into crucibles, preferably
made of aluminium with an oxidized surface.
After having melted and recrystallized each calibration specimen, carry out a heating run during which the
melting peak is recorded. Perform cooling and heating runs at the same rate as will be used for subsequent
measurements.
For each melting peak measured, determine the extrapolated peak onset temperature, T (see Figure 2),
ei,m
using the interpolated virtual baseline between peak onset and peak end.
i
For each calibration material, i, obtain the temperature correction, ∆T , by subtracting the extrapolated
corr
i i
peak onset temperature, T , from the true transition temperature, T :
ei,m cal
ii i
∆=TT −T (6)
corr cal ei,m
Then correct the temperature scale of the instrument, by linear interpolation of the temperature correction
within the temperature range covered by the calibration materials used, in accordance with Equation (7):
TT−
12 1
cal
∆=TT∆T+∆T−∆T× (7)
()
corr corr()corr corr
TT−
cal cal
where
∆∆TT, are the temperature corrections for the two calibration materials;
corr corr
TT, are the true transition temperatures of the two calibration materials.
cal cal
In order to keep errors caused by deviation from linearity of the temperature correction versus temperature
relationship small, it is recommended that the temperature range covered by the two calibration materials be
kept as small as possible. If bigger temperature ranges are required, more than two calibration materials
should be used.
NOTE 1 If more than two calibration materials are used, it is possible to use a polynomial interpolation.
NOTE 2 The temperature correction may be performed autom
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