Differential Scanning Caloriemeter DSC

Differential Scanning Caloriemeter (DSC): 

This technique is more or less similar to DTA except that it measures the amount of heat 

absorbed or released by a sample as it is heated or cooled or kept at constant temperature  

(isothermal). Here the sample and reference material are simultaneously heated or cooled at a 

constant rate. The difference in temperature between them is proportional to the difference in 

heat flow (from the heating source i.e. furnace), between the two materials. It is the well-

suited technique in the detection and further studies of liquid crystals. This technique is 

applied to most of the polymers in evaluating the curing process of the thermoset materials as 

well as in determining the heat of melting and melting point of thermoplastic polymers, glass 

transition temperature (Tg.), endothermic & exothermic behaviour. Through the adjunct 

process of isothermal crystallization it provides information regarding  the molecular weight 

and structural differences between very similar materials. The instrumentation is exactly 

similar to that of DTA except for the difference in obtaining the results.

Differential Thermal Analysis DTA

 Differential Thermal Analysis (DTA):

This technique measures the temperature difference between a sample and a reference

material as a function of temperature as they  are heated or cooled or kept at a constant

temperature (isothermal). Here the sample and reference material are simultaneously heated

or cooled at a constant rate. Reaction or transition temperatures are then measured as a

function of the temperature difference between  the sample and reference.  It provides vital

information of the materials regarding their  endothermic and exothermic behaviour at high

temperatures. It finds most of its applications in analysing and characterising clay materials,

ceramic, ores, etc.

Thermomechanical Analysis TMA

Thermomechanical Analysis (TMA): 

Thermomechanical analysis is  the measurement of a material’s behaviour, ie. expansion or 

contraction, when temperature and a load is applied. A scan of dimensional changes related 

to temperature (at constant load) or load  (at constant temperature) provides valuable 

information about the sample’s mechanical properties. One of the most important 

applications of TMA is the characterization of composite and laminate materials, through the 

study of glass transition temperature and the expansion coefficient. Another application is in 

the quantitative measurement of extension and  contraction observed in textile fibres, thin 

films and similar materials.

Thermogravimetric Analysis TGA

Thermogravimetric Analysis (TGA):

In this technique the change in sample weight is measured while the sample is heated at a

constant rate (or at constant temperature), under air (oxidative) or nitrogen (inert)

atmosphere. This technique is effective for quantitative analysis of thermal reactions that are

accompanied by mass changes, such as evaporation, decomposition, gas absorption,

desorption and dehydration. The following is the simplified diagram for the instrumentation:

The micro-balance plays a significant role, during measurement the change in sample mass

affects the equilibrium of the balance. This  imbalance is fed back to a force coil, which

generates additional electromagnetic force to recover equilibrium. The amount of additional

electromagnetic force is proportional to the mass change. During the heating process the

temperature may go as high as 15000

 C inside the furnace.

THERMAL ANALYSIS

THERMAL ANALYSIS 

The technique of thermal analysis actually comprises of a series of methods, which detect the 

changes in the physical and mechanical properties of the given substance by the application 

of heat or thermal energy. The physical properties include mass, temperature, enthalpy, 

dimension, dynamic characteristics, etc. It finds its application in finding the purity, integrity, 

crystallinity and thermal stability of the chemical substances under study. Sometimes it is 

used in the determination of  the composition of complex mixtures. This technique has been 

adopted as testing standard in quality control in the production field, process control and 

material inspection. It is applied in wide fields,  including, polymer, glass, ceramics, metals, 

explosives, semiconductors, medicines and foods.