THERMOMECHANICAL ANALYSIS (TMA)
Thermomechanical Analysis, or TMA, is one of the most widely used techniques to measure dimensional changes of solid or liquid materials as a function of temperature, time and applied force. TMA is often used to measure a material's coefficient of thermal expansion (CTE), glass transition temperature (Tg), and compression modulus by applying a constant force while varying temperature. TMA a subdiscipline of the Thermomechanometry (TM) technique.
The simplest test is the zero force thermomechanical analysis, often referred to as thermodilatometric analysis (TDA). It measures the change of dimension of a sample when heated or cooled due to activated/deactivated atomic and molecular vibrations. This measurement yields the linear expansion coefficient which is the fractional increase in length per unit rise in temperature. Another important test is creep and creep recovery of polymeric materials. In this test, sample is loaded and unloaded over periods of time to measure creep and creep recovery. Measurement of the glass transition temperature (Tg) is also one of the most important applications. During Tg analysis, the dimensional change of a polymeric material as a function of temperature at constant pressure or as a function of pressure at constant temperature is measured.