153x Filetype PPTX File size 0.99 MB Source: www.rkmmanr.org
Thermal Analysis • Thermal Gravimetric Analysis (TGA) - Measure change in weight during heating or cooling • Differential Thermal Analysis (DTA)- They are use for thermal investigation where thermal change can be observed and characterised. • Differential Scanning Calorimetry (DSC)- Measure heat absorbed or liberated during heating or cooling • Thermomechanical Analysis (TMA)- Measure change in dimensions during heating or cooling THERMOGAVIMETRIC ANALYSIS (TGA) GENERAL PRINCIPLES INVOLVED IN THERMOGRAVIMETRY • PRINCIPLE : Thermogravimetry is a technique in which a change in the weight of a substance is recorded as a function of temperature or time. • Instrument: Instrument used for thermogravimetry is “Thermobalance”. Data recorded in form of curve known as ‘Thermogram’. Thermogravimetric Analysis (TGA) • A technique that permits the continuous weighing of a sample as a function of temperature and/or as a function of time at a desired temperature The Various componants of thermobalance 1) Sample Holder: The shape,size and material of the sample holder have an important effect on the shape of the TG curve. 2)Recording Balance: It is the most important componant of a thermobalance. It must fulfill the following requirements. • Its accuracy , reproducibility, sensitivity and capacity should be similar to those of an analytical balance. • It should have rapid response to weight changes. • Simple to operate and versatile.
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