Standard Specification
International specifications for the thermal analysis of plastics establish standardized methods for determining the thermomechanical properties of polymeric materials. The testing methodologies defined in iso 11359 focus on thermomechanometry, measuring changes in dimensions as a function of temperature under a non-oscillatory load. This procedure ensures consistent evaluation of materials across different laboratories.
It is applicable to both raw polymer resins and finished molded components.
Testing Protocol
The standard is divided into multiple parts to cover different aspect of thermal behavior. Part one outlines the general principles, while part two details the determination of the coefficient of linear thermal expansion. Specimen preparation is strictly controlled, specifying dimensions and annealing procedures to remove residual moulding stress.
The instrument applies a constant force to the probe while heating the sample at a specified rate. This controlled heating reveals transition temperatures and thermal changes.
Thermomechanical Analysis
Applying iso 11359 allows manufacturers to characterize the glass transition temperature of polymers. As the temperature rises through the transition region, the rate of expansion increases dramatically. This behavior is analyzed to determine the suitability of the material for specific operating environments.
Reliable measurements depend on precise temperature calibration of the thermomechanical analyzer.
Operational Boundary
The test method is limited to solid materials that do not undergo rapid decomposition or melting within the measurement temperature range. Software-controlled force application must be calibrated to avoid crushing soft elastomeric specimens during testing. This limit ensures sample integrity is maintained throughout the measurement cycle.
