Overview
ISO 11359-1:2023 - Plastics - Thermomechanical analysis (TMA) - Part 1: General principles defines the basic principles, apparatus, specimen preparation, calibration and correction methods for performing thermomechanical analysis (TMA) of plastics. The standard covers thermoplastics and thermosetting materials (filled or unfilled) in sheet or moulded form, where deformation under a constant load is measured as a function of temperature and/or time.
Key topics
- Scope and principle: Measurement of deformation (length change) of a specimen under constant stress vs temperature/time (TMA technique).
- Apparatus requirements:
- Temperature-programmable enclosure with controlled heating/cooling and ±1 K temperature stability and accuracy.
- Displacement transducer accuracy of ±0.1% or better.
- Low thermal-expansion measurement probe (e.g., silica, quartz, ceramic) and means to compensate probe mass.
- Load-application device suitable for compression, penetration, tension, flexure, etc.
- Optional cooling device and controlled purge gas supply.
- Length-measurement devices with ±2 μm accuracy.
- Test specimens: Preparation from sheet or moulded parts, surface finish, thickness and conditioning per ISO 291; reporting of sampling orientation and location.
- Calibration:
- Temperature calibration using certified materials (examples: mercury, water, gallium, indium, tin, lead, zinc) or SS‑DTA where available.
- Displacement and load calibration using certified gauges/masses.
- Calibration specimens and methods tailored to deformation mode (penetration, flexure, tension, shear, compression).
- Data correction & processing:
- Blank correction for probe thermal expansion.
- Additional correction for displacement of the probe segment corresponding to specimen length.
- Procedures for determining true change of length and extraction of thermal events.
Applications
- Determination of coefficient of linear thermal expansion (CLTE), glass transition temperature (Tg) and penetration/melting temperatures for plastics.
- Material selection, design validation and thermal dimensional stability analysis in automotive, electronics, packaging and consumer products.
- Quality control, R&D, failure analysis and input data for finite-element thermal–mechanical simulations.
- Calibration and validation of TMA instruments in testing laboratories and instrument manufacturing.
Who should use this standard
- Polymer scientists, materials engineers and testing laboratories performing TMA.
- Quality and compliance teams specifying thermal property test methods.
- Manufacturers of TMA instruments and calibration service providers.
Related standards
Keywords: ISO 11359-1:2023, thermomechanical analysis, TMA, plastics testing, thermal expansion, glass transition, calibration, displacement transducer.
