ISO 19935-2:2020

Plastics - Temperature modulated DSC - Part 2: Measurement of specific heat capacity cp

This document establishes a method for measurement of specific heat capacity, cp, using temperature modulated differential scanning calorimetry.

Plastiques — DSC à température modulée — Partie 2: Mesurage précis de la chaleur spécifique cp

General Information

• Status: Published
• Publication Date: 22-Sep-2020
• 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: 9092 - International Standard to be revised
• Start Date: 19-Nov-2025
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 24584:2022 - Textiles - Smart textiles - Test method for sheet resistance of conductive textiles using non-contact type
• Effective Date: 06-Jun-2022

Overview - ISO 19935-2:2020 (Plastics, temperature modulated DSC)

ISO 19935-2:2020 specifies a standardized method for measuring specific heat capacity (cp) of plastics using temperature modulated differential scanning calorimetry (TM-DSC). The document describes measurement principles, apparatus requirements, calibration steps and calculation procedures so that cp data are suitable for data sheets, databases, research, quality assurance and routine material checks.

Key topics and technical requirements

• Measurement principle: cp is determined from the amplitude of the modulated heat flow signal; measurement can be done during scanning or in quasi‑isothermal (step scan) modes.
• Calculation: the standard gives a formula for cp in terms of the amplitude of the periodic heat flow (ΦA), modulation amplitude of sample temperature (TA), specimen mass (m), angular frequency (ω) and a calibration constant K(ω). Units and conditions are specified to produce cp in J·g⁻¹·K⁻¹.
• Step scan option: a step integration method is provided to obtain cp by integrating heat flow over one modulation cycle when appropriate.
• Apparatus & temperature control: TM‑DSC must be capable of periodic, stepwise or pulse temperature modulation with amplitude typically in the range ±0.1 to 2.0 K and frequencies down to about 10 mHz, superimposed on an underlying scanning rate typically < 3 K/min.
• Frequency guidance: for precision, low angular frequencies (typically ω < 60 mrad/s) are recommended so K(ω) becomes effectively frequency‑independent.
• Calibration: calibration of modulation amplitude and phase is required (referenced to ISO 19935-1 procedures); K(ω) is established using appropriate calibration materials.
• Reporting: the test report must include reference to ISO 19935-2:2020, specimen identification, DSC type/model, crucible details, purge gas, calibration procedure and sample preparation details.

Practical applications and users

Who uses ISO 19935-2:2020:

• Materials scientists and polymer researchers measuring thermal properties of plastics
• QA and QC laboratories producing cp data for raw materials and finished products
• Manufacturers of DSC instruments and laboratories validating TM‑DSC methods
• Database curators and engineers who rely on accurate cp values for thermal modeling

Typical applications:

• Building cp entries for material data sheets and thermal simulation inputs
• Monitoring curing, crystallization or other processes in quasi‑isothermal TM‑DSC mode
• Routine checks of production batches or incoming raw materials

Related standards

• ISO 19935-1 - Temperature modulated DSC: general principles (calibration methods referenced)
• ISO 11357-1 - DSC general principles and test procedures
• ISO 472, ISO 80000-5 - terminology and quantities/units used in the method

This standard ensures consistent, traceable cp measurements by TM‑DSC for plastics, supporting reproducible thermal data for research, product development and quality control.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19935-2
First edition
2020-09
Plastics — Temperature modulated
DSC —
Part 2:
Measurement of specific heat
capacity c
p
Plastiques — DSC à température modulée —
Partie 2: Mesurage précis de la chaleur spécifique c
p
Reference number
©
ISO 2020
© ISO 2020
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
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Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 1
4.1 Temperature modulation, T(t) . 1
4.2 Scanning rate . 1
4.3 Heat flow rate, Φ(t) . 1
5 Principles of determination of specific heat capacity with temperature modulated DSC .2
5.1 General . 2
5.2 Specific heat capacity with no processes . 2
5.3 Reversing and non-reversing specific heat capacity . 2
5.4 Step scan method . 2
5.5 Multiple frequencies . 2
6 Apparatus and materials. 2
6.1 General . 2
6.2 Temperature control of the modulated differential scanning calorimeter . 2
7 Calibration . 3
7.1 General . 3
7.2 Calibration of modulation amplitude . 3
7.3 Calibration of phase . 3
8 Procedure. 3
8.1 General . 3
8.2 Calculation of the specific heat capacity . 4
8.3 Examples of the results . 4
8.3.1 Modulated heat flow rate and scanning rate of modulation . 4
8.3.2 Determination of specific heat capacity . 5
9 Precision and bias . 6
10 Test report . 7
Annex A (informative) Example of the c values of polystyrene (PS). 8
p
Annex B (informative) Example of the calibration constant K(ω) determined with the
[3]
literature values of α-Al O .10
2 3
Annex C (informative) Example of a reversing heat flow rate curve based on a modulated
heat flow rate curve and a comparison with the specific heat capacity.11
Annex D (informative) Example of determination of specific heat capacity based on a
multifrequency modulated heat flow rate curve .12
Bibliography .14
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
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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
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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
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expressions related to conformity assessment, as well as information about ISO's adherence to the
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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.
iv © ISO 2020 – All rights reserved

Introduction
This document describes the realization of standardized thermoanalytical test methods which can be
used for the determination of specific heat capacity data needed for data sheets or databases as well as
for research purposes. 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 regulations.
For scientific investigations or resolution of special analytical problems, all technical capabilities of the
instruments beyond the regulations of this document may be used.
INTERNATIONAL STANDARD ISO 19935-2:2020(E)
Plastics — Temperature modulated DSC —
Part 2:
Measurement of specific heat capacity c
p
1 Scope
This document establishes a method for measurement of specific heat capacity, c , using temperature
p
modulated differential scanning calorimetry.
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 19935-1, Plastics — Temperature modulated 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, ISO 19935-1
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 Symbols and abbreviated terms
4.1 Temperature modulation, T(t)
According to ISO 19935-1.
4.2 Scanning rate
According to ISO 19935-1.
4.3 Heat flow rate, Φ(t)
According to ISO 19935-1.
5 Principles of determination of specific heat capacity with temperature
modulated DSC
5.1 General
The use of temperature modulated DSC is advantageous for the measurement of specific heat capacity
not only outside the region of a transition, because it does not require a stable baseline to achieve high
accuracy. The measurement of specific heat capacity is only based on the amplitude of the modulated
heat flow rate signal.
5.2 Specific heat capacity with no processes
According to ISO 19935-1.
5.3 Reversing and non-reversing specific heat capacity
According to
...