ISO 11359-2:2021

Plastics - Thermomechanical analysis (TMA) - Part 2: Determination of coefficient of linear thermal expansion and glass transition temperature

This document specifies a test method, using thermodilatometry[1], for the determination of the coefficient of linear thermal expansion of plastics in a solid state by thermomechanical analysis (TMA). This document also specifies the determination of the glass transition temperature using TMA. NOTE The coefficient of linear thermal expansion can be measured using various types of thermodilatometry apparatus. This document concerns only TMA apparatus.

Plastiques — Analyse thermomécanique (TMA) — Partie 2: Détermination du coefficient de dilatation thermique linéique et de la température de transition vitreuse

General Information

• Status: Published
• Publication Date: 11-Nov-2021
• 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: 12-Nov-2021
• Due Date: 22-Sep-2023
• Completion Date: 12-Nov-2021

Relations

• Revises: ISO 11359-2:1999 - Plastics - Thermomechanical analysis (TMA) - Part 2: Determination of coefficient of linear thermal expansion and glass transition temperature
• Effective Date: 20-Mar-2021

Overview

ISO 11359-2:2021 specifies a thermomechanical analysis (TMA) test method for plastics using thermodilatometry to determine the coefficient of linear thermal expansion (CLTE) and the glass transition temperature (Tg). This part of the ISO 11359 series applies specifically to TMA apparatus and describes specimen preparation, apparatus requirements, test procedure, calculation methods and reporting. The standard replaces and updates the 1999 edition with revised test-load, purge-gas conditions and clearer reference-specimen evaluation.

Keywords: ISO 11359-2:2021, thermomechanical analysis, TMA, coefficient of linear thermal expansion, glass transition temperature, thermodilatometry, plastics testing.

Key Topics and Requirements

• Scope & principle
  • Measurement of dimensional change of solid plastic specimens as a function of temperature using TMA to derive CLTE and Tg.
• Apparatus
  • Equipment compliant with ISO 11359-1; capable of compression and/or tension modes and controlled atmosphere (dry air or inert gas preferred).
• Specimens
  • Standard rectangular specimens typically 5–10 mm long and ~5 mm wide; ends parallel; at least three specimens per sample.
  • Orientation (machine/transverse) must be recorded when relevant.
• Test conditions
  • Probe load sufficient for reliable contact but low enough to avoid specimen compression (preferably 1 mN to 50 mN).
  • Gas flow around specimen typically 0–100 ml/min (dry inert gas or dry air recommended).
  • Heating rate not more than 5 K/min.
  • Preconditioning (to remove thermal memory) may include heating 50 °C below to 50 °C above Tg and holding.
• Calculation & results
  • Differential CLTE (α) from local slope dL/dT of the TMA curve.
  • Mean CLTE over a temperature interval ΔT calculated by Method A (direct from TMA) or Method B (with reference specimen).
  • Tg determination by TMA curve analysis; CLTE reported before and after Tg as applicable.
• Calibration & reporting
  • Apparatus calibration per ISO 11359-1; detailed test report requirements defined.

Applications and Who Uses It

• Materials scientists & polymer engineers - characterize thermal expansion and glass transition for research and development.
• Quality control & test laboratories - verify dimensional stability and batch consistency of plastic products.
• Design and product engineers - inform tolerancing, thermal cycling performance and multi-material assembly (e.g., polymer-to-metal joints).
• Failure analysis & certification bodies - investigate thermal distortion and compliance with specifications.
• Instrument manufacturers - ensure TMA systems meet procedural requirements.

Practical use cases include material selection for temperature-sensitive components, predicting shrinkage/warpage, thermal compatibility checks in assemblies, and validating formulations or processing changes.

Related Standards

• ISO 11359-1 - Thermomechanical analysis (TMA) - General principles (calibration, terminology).
• ISO 291 - Standard atmospheres for conditioning and testing.
• ISO 472 - Plastics - Vocabulary.

This summary helps engineers and lab managers quickly understand the scope, key technical requirements and practical value of ISO 11359-2:2021 for TMA-based thermal characterization of plastics.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 11359-2
Second edition
2021-11
Plastics — Thermomechanical
analysis (TMA) —
Part 2:
Determination of coefficient of
linear thermal expansion and glass
transition temperature
Plastiques — Analyse thermomécanique (TMA) —
Partie 2: Détermination du coefficient de dilatation thermique
linéique et de la température de transition vitreuse
Reference number
© ISO 2021
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
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Test specimens . 2
6.1 Preparation . 2
6.2 Conditioning. 3
7 Procedure .3
7.1 Calibration of apparatus . 3
7.2 Determination . 3
8 Expression of results . 4
8.1 Method of calculation . 4
8.1.1 Differential coefficient of linear thermal expansion, . 4
8.1.2 Mean coefficient of linear thermal expansion, . 5
8.1.3 Glass transition temperature . 6
8.1.4 Representative temperature . 7
8.2 Precision . . . 7
9 Test report . 7
Annex A (informative) Precision and reproducibility data for the determination of the
mean coefficient of linear thermal expansion using TMA . 9
Bibliography .10
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
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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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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
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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 11359-2:1999), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the testing procedure has been revised with regard to test load and purge gas conditions;
— the evaluation of determination of the mean coefficient of thermal expansion with reference
specimen has been specified more precisely;
— the document has been editorial revised.
A list of all parts in the ISO 11359 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
INTERNATIONAL STANDARD ISO 11359-2:2021(E)
Plastics — Thermomechanical analysis (TMA) —
Part 2:
Determination of coefficient of linear thermal expansion
and glass transition temperature
1 Scope
[1]
This document specifies a test method, using thermodilatometry , for the determination of the
coefficient of linear thermal expansion of plastics in a solid state by thermomechanical analysis (TMA).
This document also specifies the determination of the glass transition temperature using TMA.
NOTE The coefficient of linear thermal expansion can be measured using various types of thermodilatometry
apparatus. This document concerns only TMA apparatus.
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 291, Plastics — Standard atmospheres for conditioning and testing
ISO 472, Plastics — Vocabulary
ISO 11359-1, Plastics — Thermomechanical analysis (TMA) — Part 1: General principles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472, ISO 11359-1 and the
following 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 https:// www .electropedia .org/
3.1
differential coefficient of linear thermal expansion
α
expansion, normalised to the reference length L at room temperature, for any of the three dimensions
at temperature T and at constant pressure p , given in reciprocal kelvins, by the following formula:
()dL ()ddLt/
p 11p
α = ×= ×
dTL ddTt/ L
() ()
p p
where
L is the reference length at room temperature T , in the axis of measurement;
0 0
L is the length at temperature T , in the axis of measurement;

is the change in length over the time interval dt at constant pressure p ;
dL
is the change in temperature over the time interval dt at constant pressure p
dT
3.2
mean coefficient of linear thermal expansion
α
expansion, normalised to the reference length L at room temperature, for any of the three dimensions
in a specified temperature interval ΔT at constant pressure, given in reciprocal kelvins, by the following
formula:
ΔL 1
α =×
ΔTL
where
ΔL
is the change in length of the test specimen between two temperatures T and T ;
1 2
L is the reference length of the test specimen at room temperature in the axis of measurement;
ΔT
is the change in temperature, equal to TT−

Note 1 to entry: The determination is made over a temperature interval ΔT between T and T . The
1 2
representative temperature T is given by
rep
TT+
T =
rep
Note 2 to entry: By replacing the term “length” by “volume” in the formulae in 3.1 and 3.2, the coefficient of
volumetric thermal expansion can be obtained.
4 Principle
The change in a dimension of a test specimen is measured as a function of temperature using a TMA
apparatus to generate a TMA curve from which the coefficient of linear thermal expansion can be
calculated.
5 Apparatus
The components of the TMA apparatus used for this document shall be as specified in ISO 11359-1 and
shall also be capable of
a) operating in a compression mode or a tension mode or both, and
b) maintaining the specimen under a controlled atmosphere in accordance with ISO 291.
NOTE 1 Measurements on specimens of film or fibre are made in the tension mode.
NOTE 2 Typically, an atmosphere of dry air or an inert gas such as nitrogen is used.
6 Test specimens
6.1 Preparation
Test specimens shall be prepared in accordance with ISO 11359-1.
The standard test specimen is a rectangular specimen 5 mm to 10 mm in length and about 5 mm in
width. However, specimens of other dimensions may be used by agreement between the interested
parties. The ends of the test specimen shall be parallel. If applicable, the orientation of the specimen
with respect to the direction of production shall be recorded, i.e. machine direction, transverse
direction or other.
Reference shall be given to the relevant material standards for the number of test specimens, but at
least three specimens shall be prepared and tested from each sam
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