ISO 19717:2026

Plastics — Differential scanning calorimetry (DSC) or thermogravimetric analysis (TGA) — Model-free kinetics based on the non-linear incremental isoconversional method

This document establishes a model-free approach for the isoconversional kinetic analysis of chemical reactions and phase transitions. The isoconversional principle is based on the assumption that the reaction rate at a given conversion depends solely on the temperature, i.e. is independent on the scan rate. This document establishes a method for the determination of the activation energy as a function of the conversion of the reaction or transition. The method is applicable to dynamic and isothermal temperature program measurements done by differential scanning calorimetry (DSC) or thermogravimetry (TG). It can be applicable to other measurement techniques, too, that enable the determination of conversion curves. The method is applicable to the prediction of the kinetic behaviour of reactions and transitions even in temperature regions that are not experimentally accessible. The method is not applicable in the glassy state of polymers.

Plastiques — Analyse calorimétrique différentielle (DSC) ou analyse thermogravimétrique (TGA) — Analyse cinétique sans modèle basée sur la méthode isoconversionnelle incrémentale non-linéaire

General Information

• Status: Published
• Publication Date: 12-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 - Physical-chemical properties
• Current Stage: 6060 - International Standard published
• Start Date: 13-May-2026
• Due Date: 27-May-2027
• Completion Date: 13-May-2026

Overview

ISO 19717:2026 provides a standardized, model-free method for the isoconversional kinetic analysis of chemical reactions and phase transitions in plastics. This method relies on the non-linear incremental isoconversional approach, focusing on the relationship between reaction rate and temperature at a given conversion. The standard explicitly supports the determination of activation energy as it varies with reaction or transition conversion, allowing for more accurate predictions of kinetic behavior in plastics processing and analysis.

This standard is applicable to measurements conducted using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) under dynamic or isothermal temperature programs. It may also be applied to other techniques capable of producing reliable conversion curves. ISO 19717 is not suitable for the analysis of polymers in their glassy state.

Key Topics

• Isoconversional Principle: The method assumes reaction rates at a given conversion are dependent only on temperature, not on the scan rate, enabling accurate, model-free kinetic analysis.
• Activation Energy Determination: Provides procedures for calculating activation energy as a function of conversion, avoiding reliance on a constant activation energy or assumed reaction model.
• Applicability: Suitable for analyzing chemical reactions and phase transitions where the reaction mechanism or activation energy may vary with conversion, including cases with side reactions or competing processes.
• Measurement Techniques: Primary focus on DSC and TGA, but also supports any thermal analysis method that can generate conversion curves.
• Prediction Capabilities: Facilitates prediction of reaction behavior beyond experimentally accessible temperature ranges, useful for process simulation and material design.

Applications

ISO 19717:2026 offers practical benefits across various areas of plastics research, development, and quality control:

• Material Characterization: Enables in-depth understanding of reaction kinetics in polymers, supporting development of new materials with tailored properties.
• Process Optimization: Assists in optimizing thermal processing parameters by simulating reaction behavior under a range of temperature conditions.
• Decomposition and Crystallization Studies: Supports detailed analysis where reaction parameters, such as activation energy, change throughout the process.
• Quality Assurance: Enhances consistency and reproducibility of thermal analytical data in routine testing and industrial quality control.
• Research and Development: Provides a robust tool for academic and industrial R&D, eliminating uncertainties associated with traditional model-based kinetic analyses.

Related Standards

For effective implementation of ISO 19717:2026 and broader kinetic analysis, reference to complementary standards is recommended:

• ISO 472: Plastics - Vocabulary
• ISO 11357 Series: Differential scanning calorimetry for plastics, covering principles, specimen requirements, and the determination of reaction properties (notably ISO 11357-1, -5, and -7)
• ISO 11358 Series: Thermogravimetry of polymers, including activation energy determination methods (ISO 11358-1, -2, -3)
• ISO 23976: Fast differential scanning calorimetry (FSC) - Chip calorimetry
• IEC/TS 60216-7-1: Thermal endurance properties for electrical insulating materials-useful as a reference for related kinetic analysis methods and lifetime testing

By integrating ISO 19717:2026 with these related standards, organizations can achieve reliable model-free kinetic analysis and simulation for the thermal behavior of plastics, supporting improved product performance and compliance in the plastics industry.

Keywords: ISO 19717:2026, plastics, model-free kinetics, isoconversional method, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), activation energy, thermal analysis, polymer phase transitions, kinetic predictions, thermal processing, material characterization.

Standards Content (Sample)

International
Standard
ISO 19717
First edition
Plastics — Differential
2026-05
scanning calorimetry (DSC) or
thermogravimetric analysis (TGA)
— Model-free kinetics based
on the non-linear incremental
isoconversional method
Plastiques — Analyse calorimétrique différentielle (DSC) ou
analyse thermogravimétrique (TGA) — Analyse cinétique sans
modèle basée sur la méthode isoconversionnelle incrémentale
non-linéaire
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
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or ISO’s member body in the country of the requester.
ISO copyright office
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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 Principle . 2
5 Apparatus and materials . 2
5.1 Differential scanning calorimeter (DSC) .2
5.2 Thermobalance .2
6 Test specimens . 2
6.1 Differential scanning calorimetry (DSC) .2
6.2 Thermogravimetry (TG) . . .2
7 Test conditions and specimen conditioning . 2
7.1 Differential scanning calorimetry (DSC) .2
7.2 Thermogravimetry (TG) . .2
8 Calibration . 3
8.1 Differential scanning calorimetry (DSC) .3
8.2 Thermogravimetry (TG) . .3
9 Procedure . 3
9.1 General .3
9.2 Dynamic temperature program or isothermal temperature program measurements .3
9.3 Calculation of the activation energy as a function of conversion .3
9.4 Prediction of conversion curves at conditions different from measurements .4
9.4.1 Prediction of isothermal kinetics based on dynamic measurements performed
at constant heating rates.4
9.4.2 Prediction of non-isothermal kinetics at heating rates different from
measurement .4
9.4.3 Prediction of non-isothermal kinetics at arbitrary temperature variation .5
10 Precision and bias . 5
11 Test report . 5
Annex A (normative) Theoretical background for the determination of the activation energy as
a function of conversion based on the integral isoconversional principle . 7
Bibliography .10

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-
chemical properties.
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iv
Introduction
Conventional thermoanalytical methods for the characterisation of reaction kinetics, such as those
[1] [2]
described in ISO 11357-7, ISO 11358-2 or ISO 11358-3 , are applicable only for constant values of the
activation energy. Furthermore, a reaction model has to be assumed. In case of, for example, competing or
side reactions, the assumption of a constant activation energy is not applicable. Furthermore, the description
of a chemical reaction can also include processes, such as diffusion or evaporation.
[3]
Another method is specified in IEC/TS 60216-7-1 in which the thermal endurance of electric insulating
materials is predicted based on thermal analysis methods for the evaluation of the activation energy and a
lifetime test. However, this method is limited to ageing reactions where one single reaction is predominant.
To cope with these fundamental limitations, model-free kinetics have been proposed. Instead of a reaction
model and a constant activation energy, it makes use of an activation energy which depends on the extent
of conversion. This conversion-dependent activation energy is not an activation energy in the traditional
sense but rather an apparent activation energy describing the chemical reaction(s) as well as any transport
processes. This approach is based on the isoconversional principle which assumes that the reaction rate at a
[4][5][6]
certain conversion depends only on the temperature . For the temperature dependence of the reaction
rate the Arrhenius approach can be applied. Thus, the activation energy as a function of the conversion can
be calculated from several DSC or TGA measurements of a reaction done at different temperature programs.
The determination of the apparent activation energy as a function of the conversion is sufficient to make
[6]
predictions, i.e. there is no need for an explicit reaction model .
More advanced methods of the model-free kinetics approach can be applied to any temperature program, i.e.
[4][8][9]
constant scan rate, isothermal or arbitrary temperature variation measurements .
However, model-free kinetics is not an all-purpose tool. Misleading results can be obtained especially for
more complex reactions. In this case, the results and in particular the predictions should be checked for
plausibility and verified.
v
International Standard ISO 19717:2026(en)
Plastics — Differential scanning calorimetry (DSC) or
thermogravimetric analysis (TGA) — Model-free kinetics
based on the non-linear incremental isoconversional method
1 Scope
This document establishes a model-free approach for the isoconversional kinetic analysis of chemical
reactions and phase transitions. The isoconversional principle is based on the assumption that the reaction
rate at a given conversion depends solely on the temperature, i.e. is independent on the scan rate.
This document establishes a method for the determination of the activation energy as a function of the
conversion of the reaction or transition.
The method is applicable to dynamic and isothermal temperature program measurements done
by differential scanning calorimetry (DSC) or thermogravimetry (TG). It can be applicable to other
measurement techniques, too, that enable the determination of conversion curves.
The method is applicable to the prediction of the kinetic behaviour of reactions and transitions even in
temperature regions that are not experimentally accessible.
The method is not applicable in the glassy state of polymers.
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 11357-5, Plastics — Differential scanning calorimetry (DSC) — Part 5: Determination of characteristic
reaction-curve temperatures and times, enthalpy of reaction and degree of conversion
ISO 11357-7, Plastics — Differential scanning calorimetry (DSC) — Part 7: Determination of crystallization
kinetics
ISO 11358-1, Plastics — Thermogravimetry (TG) of polymers — Part 1: General principles
ISO 23976, Plastics — Fast differential scanning calorimetry (FSC) — Chip calorimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 and the following 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 https:// www .electropedia .org/

3.1
isoconversional principle
rate of a reaction or transition at a given conversion solely dependent on temperature
3.2
dynamic temperature program
controlled temperature change varying with time
Note 1 to entry: This can be both, constant scan rate and arbitrary temperature changes.
4 Principle
Several thermoanalytical measurements are carried out using a dynamic temperature program or
isothermal temperature program, or a combination of both of the reactions or transition to be investigated.
The conversions are calculated as a function of temperature or time. Based on the incremental integral
[9][10][11][12]
isoconversional method , the activation energy, E , is determined as a function of conversion
a
which is independent on the scan rate. Using the theoretical background outlined in Annex A, predictions of
the course of the reaction can be done, such as temperature-time dependent conversion, simulation of DSC/
TG reaction curves to check the quality of the prediction, estimation of reaction behaviour at temperatures
outside the available range of measurements, etc.
5 Apparatus and materials
5.1 Differential scanning calorimeter (DSC)
The apparatus and accessories shall be in accordance with ISO 11357-1 or ISO 23976.
5.2 Thermobalance
The apparatus and accessories shall be in accordance with ISO 11358-1.
6 Test specimens
6.1 Differential scanning calorimetry (DSC)
The DSC test specimens shall be in accordance with ISO 11357-1 or ISO 23976.
6.2 Thermogravimetry (TG)
The TG test specimens shall be in accordance with ISO 11358-1.
7 Test conditions and specimen conditioning
7.1 Differential scanning calorimetry (DSC)
The conditions for the DSC test and specimen conditioning shall be in accordance with ISO 11357-1 or
ISO 23976.
7.2 Thermogravimetry (TG)
The conditions for the TG test
...