Thermomechanical analysis calibration

Thermodilatometry is a particular case of thermomechanical analysis in which change in a dimension is monitored as a function of temperature under negligible load and, normally, measures the linear coefficient of expansion. It has become the most usual method and there is an ISO standard for plastics5. A British standard is identical, published as BS ISO 11359-2. ASTM has a TMA method for materials in general6 and also a formal procedure for the calibration of the analysers7. The absence of methods specifically for rubber reflects the relatively small interest in the property in the industry. 

Plastics - Thermomechanical analysis (TMA) - Determination of linear thermal expansion coefficient and glass transition temperature Plastics - Thermomechanical analysis (TMA) - Determination of softening temperature Plastics - Determination of dynamic mechanical properties -General principles Plastics - Dynamic mechanical analysis - Determination of glass transition temperature Plastics - Dynamic mechanical analysis - Calibration... 

Seyler, R. J. and Earnest, C. M. (1991), Temperature calibration of thermomechanical analyzers Part II—An interlaboratory test of the calibration procedure, in Materials Characterization by Thermomechanical Analysis, Riga, A. T. and Neag, M., eds., ASTM Publications, STP1136, Philadelphia. 

There are some drawbacks with thermomechanical analysis. Proper calibration is required to obtain reliable and reproducible data. Other sources of errors include slippage of the probe on the specimen and specimens undergoing creep in addition to length changes. 

FE analysis using an advanced material model for polymers Can account for complex geometries Can account for the experimentally determined characteristic response Enables simulations of complex thermomechanical, composite responses The advanced material models are currentiy only available as user-supplied subroutines for the FE packages Requires expertise both to calibrate and use... 

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