ISO 19935-1:2018

Plastics — Temperature modulated DSC — Part 1: General principles

This document establishes general principles of temperature modulated differential scanning calorimetry (DSC) such as description of the principle and the apparatus, sampling, calibration and general aspects of the procedure and test report common to all parts of the ISO 19335 series. NOTE Details on performing specific methods are intended to be given in the future parts of the ISO 19335 series.

Plastiques — DSC à température modulée — Partie 1: Principes généraux

General Information

• Status: Published
• Publication Date: 24-Sep-2018
• ICS: 83.080.01 - Plastics in general
• Technical Committee: ISO/TC 61/SC 5 - Physical-chemical properties
• Drafting Committee: ISO/TC 61/SC 5/WG 8 - Thermal analysis
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Apr-2028

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19935-1
First edition
2018-09
Plastics — Temperature modulated
DSC —
Part 1:
General principles
Plastiques — DSC à température modulée —
Partie 1: Principes généraux
Reference number
ISO 19935-1:2018(E)
©
ISO 2018

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ISO 19935-1:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii © ISO 2018 – All rights reserved

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ISO 19935-1:2018(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Calculation of heat flow rate and heat capacity . 1
4.1 Temperature modulation, T(t).1
4.2 Heating rate . 2
4.3 Heat flow rate Φ(t) and heat capacity . 2
4.3.1 General. 2
4.3.2 Heat capacity with no processes . 3
4.3.3 Heat capacity with additional processes. 4
4.3.4 Time dependent heat capacity . 5
5 Principles . 5
5.1 General . 5
5.2 Mode of temperature modulation . 5
5.2.1 Variable heating rate of periodic modulation . 5
5.2.2 Variable temperature modulated mode . 6
5.3 Heat capacity determined with the temperature modulation — Complex heat capacity . 7
5.4 Reversing and non-reversing heat capacity . 8
5.5 Advantage of the temperature modulation applied to DSC . 8
6 Apparatus and materials.11
6.1 General .11
6.2 Temperature control of modulated differential scanning calorimeter .11
7 Calibration .12
7.1 General .12
7.2 Calibration of modulation amplitude .12
7.3 Calibration of phase .12
8 Procedure.12
8.1 General .12
8.2 Experimental conditions .13
8.3 Interpretation of results .13
9 Test report .13
[7]
Annex A (informative) Generalized theory of temperature modulated DSC .14
Bibliography .16
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ISO 19935-1:2018(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 on 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 the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-
chemical properties.
A list of all parts in the ISO 19935 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.
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ISO 19935-1:2018(E)

Introduction
The ISO 19935 series specifies temperature modulated differential scanning calorimetry (DSC)
methods for the thermal analysis of polymers such as thermoplastics, thermosets and elastomers.
It is designed for observing and quantifying various phenomena or properties of the abovementioned
materials such as
— physical transitions (glass transition, phase transitions like melting, crystallization, and cold
crystallization, etc.);
— chemical reactions (cross-linking and curing of elastomers and thermosets, etc.);
— heat capacity;
— separation of overlapping thermal transitions.
This document describes the realization of several standardized thermoanalytical test methods which
can be used for the determination of comparable data needed for data sheets or databases as well as for
research purposes, but it can also be applied to quality assurance or to routine checks of raw materials
and finished products, if desired. The procedures mentioned in this document apply as long as special
product standards or standards describing special atmospheres for conditioning of samples do not
require alternate provisions.
For scientific investigations or resolution of special analytical problems, all technical capabilities of the
instruments beyond the provisions of this document may be used.
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INTERNATIONAL STANDARD ISO 19935-1:2018(E)
Plastics — Temperature modulated DSC —
Part 1:
General principles
1 Scope
This document establishes general principles of temperature modulated differential scanning
calorimetry (DSC) such as description of the principle and the apparatus, sampling, calibration and
general aspects of the procedure and test report common to all parts of the ISO 19335 series.
NOTE Details on performing specific methods are intended to be given in the future parts of the
ISO 19335 series.
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 11357-1, Plastics — Differential scanning calorimetry (DSC) — Part 1: General principles
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 11357-1 and
ISO 80000-5 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Calculation of heat flow rate and heat capacity
4.1 Temperature modulation, T(t)
A periodic temperature profile superimposed to a linear temperature change or constant temperature,
is given by Formula (1):
Tt =+Ttβ ⋅+Tf⋅ t (1)
() ()
00 A
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ISO 19935-1:2018(E)

where
t is the time;
T is a start temperature;
0
β is the underlying heating or cooling rate;
0
T is the amplitude of sample temperature profile;
A
f(t) is the periodic function of the temperature profile.
The periodic temperature profile can have any waveform. Multi-frequency temperature modulation
can be used in one and the same measurement.
4.2 Heating rate
The heating rate is not constant as in the case of conventional differential scanning calorimetry (DSC),
which follows from Formula (1):
dT t df t
() ()
=+β T ⋅ (2)
0A
dt dt
If the temperature profile is a sinusoidal function with angular frequency, ω [see Formula (3)]:
ft = sintω (3)
() ()
Formula (2) is derived as shown in Formula (4):
dT t
()
=+βωTt⋅ ⋅cos ω (4)
()
0A
dt
4.3 Heat flow rate Φ(t) and heat capacity
4.3.1 General
For a temperature perturbation that consists of an underlying part Φ , a periodic part Φ ,
underlying periodic
and an additional endothermic or exothermic excess heat exchange part Φ , the heat flow rate Φ(T, t)
ex.
can be expressed as Formula (5):
ΦΦTt, =+ΦΦ+ (5)
()
underlying periodic ex.
assuming the pure thermodynamic heat capacity is as shown in Formula (6):
dT t
()
ΦΦTt, =CT ⋅ + (6)
() ()
pex.
dt
df t
T ()
A
=+CCβ ⋅ ⋅ +Φ
pp0 ex.
K ω dt
()
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ISO 19935-1:2018(E)

where
C is the heat capacity;
p
K(ω) is the frequency-dependent calibration function of the heat capacity (see 7.1).
The different cases are distinguished in 4.3.2 to 4.3.4.
Formulae (5) and (6) are enabled only for slow modulation with ωτ < < 1, where τ is the time constant of
the instrument. For higher frequencies, the calibration factor K(ω) [see 7.1, Formula (26)] has to be used.
4.3.2 Heat capacity with no processes
In this case, Formula (6) applies with Φ = 0, if the temperature profile is a sinusoidal function, then
ex.
Formula (4) yields:
T
A
Φ Tt,c=+CCβ ⋅ ⋅⋅ωωos t (7)
() ()
pp0
K ω
()
Formula (7) means that the measured heat flow rate is the sum of two components, the first term is
referred to as the underlying, Φ , and the second one is the periodic, Φ . The average
underlying periodic
within one period by integration derives Φ as Formula (8):
underlying
tt+ /2
p
ΦΦ= Tt, dt =⋅C β (8)
()
underlying p 0
∫
tt− /2
p
If the underlying part is subtracted from the measured heat flow rate, the periodic part is given as:

ΦΦTt,,= Tt −ΦΦTt,c=⋅CT ⋅⋅ωωos tt=⋅cos ω (9)
() () () () ()
underlying pA
From the amplitude of the periodic part, Φ , the heat capacity of the sample is:
A
Φ
A
C = (10)
p
T ⋅ω
A
The specific heat capacity, c :
p
C
Φ
p
A
c == (11)
p
mm⋅⋅T ω
A
where m is the mass of the sample, called “specific heat capacity”.
NOTE True C can be found either by calibration procedure using the calibration factor K(ω) [see 7.1,
p
Formula (26)].
Φ
A
C = ⋅K()ω (12)
p
T ⋅ω
A
Φ
A
c = ⋅K ω
()
p
mT⋅⋅ω
A
or calculated following the manufacturer’s instructions.
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ISO 19935-1:2018(E)

Formulae (7) to (11) are valid for a sinusoidal temperature modulation. There are different types of
temperature modulation functions and evaluation procedures:
a) stepwise temperature changes with isothermal segments;
b) single frequency modulations;
c) use of non-sinusoidal modulation wavef
...