Thermal Properties Measurements

Introduction

The structural properties of elastomeric and plastic materials can change significantly with relatively small changes in temperature. If the material experiences a range of temperatures that includes the glass transition temperature, the properties can change by orders of magnitude! Even some medical materials experience significant structural changes between room temperature and human body temperature.
Material properties measurements like the stress-strain curves discussed in other parts of this site need to be performed at the application temperature. In addition to the structural properties, the materials expand or contract with changes in temperature. Often plastic or elastomeric materials change much more than surrounding steel parts causing large stress conditions. Simple thermal expansion experiments can help us to predict this.

This section is divided into sections as follows:

  • Thermal Expansion and Tg
  • Thermal Conductivity, Thermal Diffusivity, and Specific Heat


  • Thermal Expansion and Tg

    A PerkinElmer Diamond Thermomechanical Analyzer (TMA) is used to determine dimensional changes in materials as a function of temperature or time. It is used to measure changes in length, width, thickness and linear expansion of materials.

     

    Image of a plastic specimen in a thermal expansion experiment.
    Plastic Specimen in a Thermomechanical Analyzer


    Thermal Conductivity, Thermal Diffusivity, and Specific Heat

    At Axel Products, the basic thermal properties of thermal conductivity, thermal diffusivity and specific heat of rubber and plastic materials over temperatures ranging from -40C to 200C are measured using a transient plane source method. The instrument used is manufactured by C-Therm Technologies as the TCi Thermal Property Analyzer.

     

    TCi sensor
    TCi Sensor in an Environmental Box