Thermogravimetric analysis (TGA) is a technique that measures the mass of a substance as it is heated or cooled over time in a controlled atmosphere. TGA works by monitoring the weight changes that occur as a sample is heated - weight losses indicate volatilization or decomposition of components. The major components of a TGA instrument are a high-precision balance, furnace, sample holder, temperature and weight sensors, and gas flow system. TGA is useful for applications like determining filler or residual solvent content, decomposition temperatures, and oxidative stability of materials.

1. THERMOGRAVIMETRIC
ANALYSIS
Anita Kumbhakar
18901919005
Advanced Instrumentation Techniques
PT 810C
4TH Year B. Pharm

2. 01
04
02
05
Table of contents
Introduction Factors affecting
TG Curve
Principle Advatages
03
06
Types Applications
Instrumentation
07
08
What we get
from TGA

3.  Thermogravimetric Analysis is a technique in which
the mass of a substance is monitored as a function
of temperature or time as the sample specimen is
subjected to a controlled temperature program in a
controlled atmosphere.
 TGA is a technique in which, upon heating a
material, its weight increases or decreases.
 TGA measures a sample’s weight as it is heated or
cooled in a furnace.
Introduction

4. • A TGA consists of a sample pan that is supported by a
precision balance. That pan resides in a furnace and is
heated or cooled during the experiment. The mass of the
sample is monitored during the experiment. A sample purge
gas controls the sample environment. This gas may be inert
or a reactive gas that flows over the sample and exits
through an exhaust.
• These instruments can quantify loss of water, loss of solvent,
loss of plasticizer, decarboxylation, pyrolysis, oxidation,
decomposition, weight % filler, amount of metallic catalytic
residue remaining on carbon nanotubes, and weight % ash.
Contd.

5. PRINCIPLE
• A TGA analysis is performed by gradually raising the temperature of
a sample in a furnace as its weight is measured on an analytical
balance that remains outside of the furnace.
• In TGA, mass loss is observed if a thermal event involves loss of a
volatile component.
• Chemical reactions, such as combustion, involve mass losses,
whereas physical changes, such as melting, do not.
• The weight of the sample is plotted against temperature or time to
illustrate thermal transitions in the material – such as loss of solvent
and plasticizers in polymers, water of hydration in inorganic
materials, and, finally, decomposition of the material.

6. TYPES
The three types of thermographic analysis represent different ways to
apply heat to the sample, as weight change is measured over time.
• Isothermal or static thermogravimetry: Temperature is
constant
• Dynamic thermogravimetry: Temperature is changed in a linear
manner
• Quasi Static thermogravimetry: A series of increasing
temperatures

7. INSTRUMENTATION
The major components of the thermogravimetric
analyzer (thermobalance) are:
• Balance
• Furnace assembly
• Sample container, temperature sensor, furnace liner,
thermocouple, etc.
• Recorder and display
• A purge gas system for providing an inert
atmosphere.
The balance and the furnace assembly are the two key
components of thermobalance. A shallow platinum
crucible (also known as a sample container) is used to
hold the samples and is connected to an automatic
recording microbalance. In thermogravimetry, null point
balances are the most often used form of the balance
system. The null point approach causes the balance
beam to move away from its normal position whenever
there is a change in weight.

8. FACTORS AFFECTING TG CURVE
INSTRUMENTAL FACTORS
SAMPLE CHARACTERISTICS
FURNACE HEATING RATE:
The temperature at which the
compound decompose depends
upon the heating rate. When the
heating rate is high, the
decomposition temperature is
also high
FURNACE ATMOSPHERE:
The atmosphere inside the
furnace surrounding the sample
has a profound effect on the
decomposition temperature of
the sample
WEIGHT OF SAMPLE:
A small weight of the sample
is recommended using a small
weight eliminates the existence
of temperature gradient
throughout the sample.
SAMPLE PARTICLE SIZE:
The particle size of the sample
should be small & uniform. The use
of large particle or crystal may
result in apparent very rapid weight
loss during heating.

9. ADVANTAGES OF TGA
A relatively small set of data is to be treated
Continuous recording of weight loss as a function
of temperature ensures equal weightage to
examination over the whole range of study
As a single is analyzed over the whole range of
temperature, the variation in the value of the kinetic
parameters, if any, will be indicated
1
2
3

10. APPLICATIONS
Filler content of polymer resins
Residual solvent content
Carbon black content
Decomposition temperature
Moisture content of organic and inorganic materials
Plasticizer content of polymers
Oxidative stability
Performance of stabilizers
Low molecular weight monomers in polymers

11. It is beneficial in routine
analysis of content
determination to get
accurate understanding of
sample composition.
It helps in understanding
the reactivity corrosivity of
sample materials when
exposed to specific
environments.
TGA analyzes the changes
in size, shape and overall
mass when exposed to
varying temperatures.
It gives accurate details of
the mass change of the
materials under test.
It provides necessary data
for a wide range of
materials characterization
objectives.
Determines the stability of
pharmaceutical drugs.
What do we get from TGA?

12. Thanks!