Presentation Transcript
Slide 1:Thermal Gravimetric Analysis (TGA)
Differential Thermal Analysis (DTA)
TGA :TGA
Thermogram for decomposition of pure calcium oxalate. :Thermogram for decomposition of pure calcium oxalate.
DTA :DTA DTA involves heating or cooling a test sample and an inert reference under identical conditions, while recording any temperature difference between the sample and reference.
This differential temperature is then plotted against time, or against temperature. Changes in the sample which lead to the absorption or evolution of heat can be detected relative to the inert reference.
DTA can therefore be used to study thermal properties and phase changes which do not lead to a change in enthalpy.
A DTA curve can be used as a finger print for identification purposes.
Variation of temperature of the sample wrt reference :Variation of temperature of the sample wrt reference
Measure sample temperature relative to a reference, for the same heat transferred :Measure sample temperature relative to a reference, for the same heat transferred Thermal events: Exothermic event and endothermic event
Reaction/decomposition
Melting
Crystallization
Change in crystal structure
Glass transition
Differential Thermogram :Differential Thermogram
Applications :Applications DTA finds use in determining the thermal behavior & composition of various substances
DTA is widely used for studying & characterizing polymers. And hence can be used for identifying polymers.
It is also used in the generation of phase diagrams & the study of phase transitions.