Overview

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• Source: Microbioz India


• Date: 12 Aug,2024

Why a material responds to heat in the process of characterizing materials is important for their use in different applications. Two powerful techniques that provide crucial information about thermal events are Thermogravimetry (TGA) and Differential Scan Calorimetry (DSC). Each technique has its own strengths and can be used to study different aspects of the thermal properties of a material. Selecting the correct method can greatly influence your data’s accuracy and appropriateness.

Have a look at this guide to help you decide which method would probably work best for your materials’ characterization need.

Thermo Gravimetric Analysis

What Is It?

TGA determines changes in mass with temperature within a controlled program for heating or cooling.

How Does It Work?

In TGA, a sample is placed on a balance inside a furnace. As the temperature rises or falls, there is a change in weight recorded by the balance. The resulting thermogram plots these changes against temperature or time thus revealing significant mass related thermal events.

When Should You Use TGA?

1. Decomposition analysis: Ideal for studying temperatures at which materials decompose. This helps in understanding their thermal stability as well as composition.
2. Polymer Characterization: Helps determine polymer degradation and presence of fillers or additives
3. Material Composition: Can be used to measure volatile components, moisture content, ash residue
4. Environmental Analysis: To verify stability of products and confirm if any emissions were produced

Advantages:

1. Gives direct information about mass change and decomposition temperatures
2. Can examine powders, liquids and solids among other things
3. Allows one to test thermal stability under various atmospheres

Differential Scanning Calorimetry (DSC): Measuring Heat Flow

What Is It?

DSC measures heat flow through or from the sample relative to reference substance while changing its temperature. It is used to determine the thermal transitions and heat capacity of samples.

How Does It Work?

In DSC, both the sample and a reference are exposed to a programmed temperature protocol. The heat flow difference between the sample and reference is recorded and plotted as a function of time or temperature resulting in thermogram showing endothermic / exothermic events.

When Should You Use DSC?

1. Phase Transition Analysis: Good for finding out melting points, glass transitions, crystallization.
2. Heat Capacity Measurement: Determines the amount of energy needed to change material’s temperature
3. Pharmaceutical Analysis: Useful for studying polymorphism, drug formulation, purity
4. Food Science: Evaluates thermal properties and transitions in food ingredients or formulations

Advantages:

1. Gives detailed information about thermal transitions such as melting, crystallization, glass transition.…
2. Measures heat flow and heat capacity providing insights into energy changes related to thermal processes
3. Suits broad range of materials including but not limited to: polymers; pharmaceuticals; foods…

Choosing the Right Method: TGA Vs DSC

When deciding between TGA and DSC consider the following:

1. Objective of Analysis: If you need to have an understanding about mass changes with respect to thermal stability TGA is preferable. For more details on thermal transitions as well as heat capacity use DSC instead.
2. Type: TGA is multipurpose for different sample types like powders and liquids. DSC is good at detailed analysis of solid, liquid and phase transitions.
3. Requirements: TGA gives information on the temperature of decomposition and mass changes while DSC provides insight into thermal transitions and heat capacities.

TGA and DSC combined:

A majority of times, material’s thermal behavior is best understood when a combination of TGA and DSC is used. By using both methods, you can correlate mass changes with heat flow data, offering a more complete picture of the material’s thermal properties.