Differential Scanning Calorimetry
What is Differential Scanning Calorimetry?
In the simplest terms, Differential Scanning Calorimetry (DSC) is a thermal analysis technique used by material testing labs like ACE Laboratories to investigate the response of polymers to heating.
DSC is highly useful in its ability to deliver precise readings on a material’s specific heat capacity. DSC measures the difference in the amount of energy (heat) required to increase the temperature of a sample.
Differential Scanning Calorimetry can be used for various reasons, including the observation of crystalline polymer melting and the glass transition. DSC can also be used to study fusion, oxidation, and other chemical reactions. DSC analysis is also an excellent test for ensuring quality control among polymer materials, since DSC can help evaluate sample purity and study polymer curing.
DSC Analysis Explained
When using DSC test results to analyze your polymer material, a testing laboratory will closely study the DSC curve—the visual representation of DSC test results.
These curves can display heat flux versus either temperature or time, depending on the needs of your particular material, goal, or end use. DSC curves can be used as tools for benchmarking and comparison as you develop products, innovate better materials, and manage for quality control.
DSC Analysis of Polymers
So what happens during Differential Scanning Calorimetry analysis?
The DSC testing set-up is composed of a measurement chamber and a computer. Two pans are heated in the measurement chamber. The sample is placed in the pan for heating or cooling. During the test, the sample temperature is measured from below, as well as an empty control pan. By comparing the difference in temperature across both pans, heat flow is determined.
Temperatures for DSC testing can reach 725 C, with low temperatures down to -120 C. When testing your sample, ACE guarantees the repeatability of your test, including repeatability of the temperatures at which we test your sample.
After the actual test is performed, an ACE laboratory technician will analyze the resulting DSC curve for information about transition temperatures, crystallization temperatures, melting temperatures, or other factors pertinent to your material’s properties.
These results, along with other compositional test results, can be used to compare your polymer material to other materials and ensure the quality of your end product.
When to Use a DSC Test
When determining if a DSC Test should be included in your strategy for reaching product goals, decide if you need to know the following:
- Will my material need to withstand cold temperatures?
- Will my material experience a wide variety of temperatures?
- Will my material cool from a melt at any point in its creation or end use?
If the answer to any of these questions is yes, you may want to test your material with Differential Scanning Calorimetry. In addition, it is always a good idea to keep this test method in mind for quality control reasons, along with other physical and analytical tests available at ACE.
If you have questions about DSC’s fit for your needs, contact us. At ACE Laboratories, we can design a material testing strategy just for you—and don’t worry, we’re never afraid of a challenge.
DSC Testing Procedures
If you have determined that a DSC analysis is right for your product or material, you will probably want to understand the different types of DSC testing procedures. Our first test method, ASTM D7426, deals with glass transition temperatures. Our second test, ASTM D3418, uses DSC to determine transition temperatures, enthalpies of fusion, and crystallization of polymers.
Glass Transition Temperature Testing
Our ASTM D7426 test method is used to analyze the glass transition temperatures of materials using DSC. During glass testing, no formal phase change occurs. Rather, the transition appears as a step in the recorded DSC signal.
If your material drops below its determined glass transition temperature in its real-life application, it will become brittle and glass-like. That makes DSC testing essential for determining the strength and usefulness of materials that will likely encounter cold temperatures.
Transition Temperatures, Enthalpies of Fusion, and Crystallization
Another DSC test, ASTM D3418, uses Differential Scanning Calorimetry as a method for determining three main factors: transition temperatures, enthalpies of fusion, and crystallization of polymers.
Testing transition temperatures allows us to determine at what temperature your material loses certain qualities. The qualities tested will depend on your material and the desired end use. You will work with an ACE team member to identify the best test methods for you.
Enthalpies of fusion are measured based on your sample’s DSC curves. This gives us a determination of the change in enthalpy, or total heat content, of your material when changing its state from a solid to a liquid by applying energy.
Data regarding the crystallization of polymers is taken when your material cools from a melt. We can observe crystallization and determine its effects on the optical, mechanical, thermal, and chemical properties of your polymers.
Understanding the properties of your material in the context of these three factors helps you create a high quality product, able to withstand the necessary elements for its given end use.
DSC Analysis at ACE Laboratories
ACE’s material testing laboratory is internationally accredited and committed to your success. We offer DSC testing along with many other physical and chemical test methods.
Work with us to determine the best course of testing and analysis for your polymer material. We pride ourselves on meeting challenges, communicating well and often, and meeting the high standards we set for ourselves.
If you are interested in material testing with ACE, contact us. How can we help you reach your next goal?
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