ISO 11359-3:2026

Overview

ISO/PRF 11359-3: Plastics - Thermomechanical analysis (TMA) - Part 3: Determination of penetration temperature is an international draft standard developed by ISO/TC 61/SC 5. This document outlines a standardized method for determining the penetration temperature of thermoplastics using thermomechanical analysis (TMA). The penetration temperature is a critical property of plastics, indicating the temperature at which a probe begins to penetrate or shows an abrupt increase in penetration under controlled conditions. The method can also serve to assess the softening point of the plastic material.

This standard is integral for laboratories, manufacturers, and quality assurance professionals who require consistent, reliable data on thermoplastic behavior under thermal load.

Key Topics

• Penetration Temperature Definition
  The penetration temperature is defined as the point at which an abrupt displacement of the penetration probe occurs during a TMA test, signaling significant softening in the specimen. This helps identify the transition point where a thermoplastic becomes susceptible to deformation under specified thermal and mechanical conditions.

• Thermomechanical Analysis (TMA) Method
  The procedure employs a TMA apparatus equipped with a penetration probe, applying a constant force on a specimen as temperature increases at a controlled rate. The TMA records displacement as a function of temperature to determine the penetration point.

• Sample Preparation and Conditioning
  Proper preparation and conditioning of samples are emphasized, referring to relevant standards like ISO 291 for standard atmospheres and ISO 472 for terminology. Specimens must have smooth, flat surfaces and be conditioned under specified environmental conditions to ensure consistent results.

• Result Expression and Test Reporting
  Final test results, including the mean penetration temperature and details of any multi-stage softening behavior, must be clearly documented. The report should reference ISO 11359-3, provide specimen and probe details, testing parameters, any deviations from procedure, and the date of the test.

Applications

• Material Characterization
  This standard provides essential data for characterizing thermoplastics, particularly in terms of their heat resistance and performance at elevated temperatures.

• Quality Control
  Manufacturers use penetration temperature determination for batch-to-batch consistency checks and material certification, ensuring compliance with industry standards.

• Research and Development
  Polymer scientists and engineers utilize this method to compare new formulations, blends, or additives, facilitating product development and improvement.

• Specification and Compliance
  The method is used in procurement and regulatory compliance, helping purchasers and regulators verify materials against global and sector-specific requirements.

Related Standards

For comprehensive thermal analysis and consistent terminology, users of ISO/PRF 11359-3 should also consult:

• ISO 11359-1: Plastics - Thermomechanical analysis (TMA) - Part 1: General principles
  Provides guidance on TMA techniques and apparatus requirements.

• ISO 291: Plastics - Standard atmospheres for conditioning and testing
  Details standard environmental conditions for test specimen preparation and conditioning.

• ISO 472: Plastics - Vocabulary
  Offers standardized terms and definitions for the plastics industry.

Using ISO/PRF 11359-3 in conjunction with these standards ensures accurate, reproducible, and internationally comparable results in the determination of the penetration temperature and softening point of thermoplastics. This delivers significant practical value across quality assurance, R&D, and compliance activities within the plastics sector.