Temperature wave analysis method measurements

The temperature modulation technique is advantageous for observing the complex physical properties in the relaxation region. The temperature wave analysis (TWA) method is a nonsteady-state method for measuring the thermal diffusivity of materials. 

The thermal and thermomechanical properties of the polymer/HAp composites (glass transition temperature, melting and crystallization behaviour, thermal stability, crosslinking effects, phase composition, modulus, etc.) can be evaluated by thermal analysis methods, like TG, DSC and DMA. Recently, a modulated temperature DSC (MTDSC) technique has been developed that offers extended temperature profile capabilities by, for example, a sinusoidal wave superimposed on the normal linear temperature ramp [326]. The new capabilities of the MTDSC method in comparison with conventional DSC include separation of reversible and non-reversible thermal events, improved resolution of closely occurring and overlapping transitions, and increased sensitivity ofheat capacity measurements [92,327]. 

All temperature-wave methods, or periodic-heat-flow methods in general, involve the measurement of the attenuation or phase shift of a periodically varying temperature wave within the specimen. A wide variety of experimental designs have been employed. A disadvantage, sometimes serious, of most is the complex mathematical analysis and assumptions required for the interpretation of data. The use of high speed computers has, however, lessened this problem. These methods are suitable for thermal diffusivities in the range of 1 x 10 to 5 X 10 m /s, and in many cases are adaptable to multiproperty measurement. 

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