ISO 19935-2:2026

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: 28-May-2026
• 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: 6060 - International Standard published
• Start Date: 29-May-2026
• Due Date: 19-May-2027
• Completion Date: 29-May-2026

Relations

• Revises: ISO 19935-2:2020 - Plastics — Temperature modulated DSC — Part 2: Measurement of specific heat capacity cp
• Effective Date: 07-Dec-2025

Overview

ISO 19935-2: Plastics - Temperature Modulated DSC - Part 2: Measurement of Specific Heat Capacity cp is an international standard published by ISO. This document specifies a standardized method for determining the specific heat capacity (cp) of plastics using temperature modulated differential scanning calorimetry (TM-DSC). The method is designed to ensure precision, repeatability, and comparability of specific heat capacity measurements required for technical data sheets, quality control, and research applications.

Temperature modulated DSC provides a reliable approach to determine cp by superimposing a modulation on the regular temperature program of a DSC instrument. This enables the separation of overlapping thermal events, such as reversing and non-reversing processes, and provides accurate cp values, even in regions where a traditional DSC may have limitations.

Key Topics

• Specific Heat Capacity Measurement: Details a precise technique for measuring cp using TM-DSC, including considerations for sample mass, temperature modulation parameters, and instrument calibration.
• Temperature Modulation Methods: Outlines approved modes of temperature modulation, such as sinusoidal and stepwise modulations, and their impact on data quality.
• Calibration and Validation: Provides steps for calibrating DSC instruments, including modulation amplitude, phase, and the use of standard reference materials like α-Al₂O₃ (sapphire) for accurate cp determination.
• Data Analysis and Reporting: Includes guidelines for calculations, interpretation of modulated heat flow rate signals, and required elements for comprehensive test reporting.

Applications

The standardized method in ISO 19935-2 is broadly applicable across the plastics industry and research sectors for:

• Material Characterization: Generating specific heat capacity data essential for product datasheets, simulation inputs, and engineering calculations.
• Quality Control: Consistent cp measurement supports material consistency checks, batch releases, and compliance with regulatory requirements.
• Research and Development: Facilitates advanced thermal analysis in the development of new polymer formulations and investigation of thermal transitions, phase changes, or reaction monitoring (e.g., curing, crystallization).
• Database Creation: Provides reliable cp data for inclusion in material property databases and software tools.
• Comparative Studies: Enables comparison of cp values across different materials, processing conditions, or aging states using a harmonized approach.

Related Standards

• ISO 19935-1: Plastics - Temperature modulated DSC - Part 1: General principles. Establishes the basic principles and requirements for temperature modulated DSC applied to plastics.
• ISO 11357-1: Plastics - Differential scanning calorimetry (DSC) - Part 1: General principles. Supplies foundational techniques for DSC analysis.
• ISO 472: Plastics - Vocabulary. Provides definitions for terms used throughout plastics testing standards.
• ISO 80000-5: Quantities and units - Part 5: Thermodynamics. Describes relevant units and symbols for thermodynamic properties such as specific heat capacity.

Practical Value

Implementing ISO 19935-2 ensures:

• Trustworthy and Reproducible Results: Laboratories around the world can compare and share cp values with confidence, thanks to standardized measurement procedures.
• Improved Material Performance Insight: Accurate cp data inform design choices and predict in-service thermal behavior for plastic components.
• Support for Compliance and Certification: Adoption of ISO standards facilitates compliance with industry-specific, national, and international regulations.

For organizations involved in polymer production, testing, or research, ISO 19935-2 offers a robust, flexible method to characterize thermal properties efficiently and reliably, supporting innovation and quality in plastics technology.

Standards Content (Sample)

International
Standard
ISO 19935-2
Second edition
Plastics — Temperature modulated
2026-05
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 2026
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
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
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 .3
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 .4
9 Precision and bias . 5
10 Test report . 5
Annex A (informative) Example of the c values of polystyrene (PS) . 7
p
Annex B (informative) Example of the calibration constant K(ω) determined with the literature
[4]
values of α-Al O . 8
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 . 9
Annex D (informative) Example of determination of specific heat capacity based on a
multifrequency modulated heat flow rate curve .10
Bibliography .13

iii
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
https://www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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.
This second edition cancels and replaces the first edition (ISO 19935-2:2020), of which it constitutes a minor
revision.
The main changes are as follows:
— unit for the modulated temperature in the key to Figure 1 has been corrected.
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
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.

v
International Standard ISO 19935-2:2026(en)
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 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 http:// www .electropedia .org/
4 Symbols and abbreviated terms
4.1 Temperature modulation, T(t)
Temperature modulation shall be in accordance with ISO 19935-1.
4.2 Scanning rate
Scanning rate shall be in accordance with ISO 19935-1.
4.3 Heat flow rate, Φ(t)
Heat flow rate shall be in accordance with ISO 19935-1.

5 Principles of determination of specific heat cap
...