Do you have questions about a polymer product? Perhaps you suspect that epoxy failure may be the root of poor performance? Maybe you’d like to reverse engineer a product and need help identifying an unknown polymer? Or it could be you received a shipment of parts from a new supplier, and you want to ensure it meets specifications?
You’ve heard that Differential Scanning Calorimetry (DSC) is a popular analytical technique for polymers. But how do you know if DCS testing is the right choice for your next project? Read on for answers to the most frequently asked DSC questions.
Answers to the Top 10 DSC Questions
1. What is DSC?
DSC is a thermal analysis technique that measures heat flow as a function of time and/or temperature. This correlates to how a material responds to changes in temperature. The process involves applying heat or cold to see how it affects a material’s heat capacity. These changes in heat capacity are measured as changes in heat flow.
So why use DSC to measure heat flow? This technique can detect numerous transitions such as melting points, glass transitions, phase changes, curing and more. Since nearly all materials go through some phase transition when exposed to temperature, it has applications across numerous industries, including polymers, pharmaceuticals, electronics and general manufacturing.
2. What is the Difference Between a Heat Flow DSC and Heat Flux DSC?
DSC information is generally captured in one of two ways: heat flow DSC or heat flux DSC. While both methods measure the impact of thermal energy on materials, there are a few differences between the two.
Heat Flux DSC
Heat flux DSC compares the discrepancies in temperature, or the heat flux, between a testing sample and a reference material as they are heated together in a single furnace. During the test, the sample’s temperature is unchanged until melting is complete, while the temperature of the reference material linearly increases. The temperature difference between the samples is measured as a function of temperature.
Heat Flow DSC
Heat flow DSC takes accuracy a step further. This approach uses an instrument with a double furnace, also called a power-controlled DSC. The double furnace design allows a feedback loop, enabling the system to compare the necessary energy to maintain a sample at a set temperature against the required power for a reference furnace. As a result, the system can precisely measure the temperature movement in and out of a material.
Heat flow DSC is also more sensitive to small transitions, heats and cools more quickly, and provides more definitive values for heat capacity and heat content changes, known as enthalpy.
3. What are the Advantages of DSC?
DSC provides incredible ease and speed in tracking and analyzing material transitions due to temperature changes. In particular, it’s a valuable tool for tracking heat capacity, glass transitions, melting point and crystallinity.
4. What is Heat Capacity?
Heat capacity is a physical property of matter and is the amount of heat necessary to increase the temperature of a unit mass of a material by one degree. Heat capacity is an extensive property, meaning that it scales with the overall size of the material. While heat capacity is often treated as constant, it can fluctuate depending on the system’s temperature, pressure, and volume.
5. When Does Heat Capacity Matter?
Knowing a material’s heat capacity and enthalpy can help you determine the efficiency of your processes. This information is beneficial if your company uses polymers or manufactures pharmaceuticals.
6. What is Glass Transition?
A glass transition is what happens when a noncrystalline solid or amorphous material melts. Amorphous solids have no organization — this is the reason for their transparency. When you apply heat to an amorphous solid, its heat capacity increases. When the material accumulates enough energy, it experiences a glass transition in which it becomes hard, rigid and brittle. The glass transition is a reversible transition, like melting.
7. When Does Glass Transition Matter?
The glass transition temperature is an excellent indication of a material’s composition and can identify potential performance issues — especially when using synthetic high polymers for manufacturing or storage. That’s because additives can change glass transition temperature. Also, a material’s properties can affect the degree of polymerization, stiffness and flow. Glass transition temperatures are often used to determine optimal storage conditions in pharmaceutical and food products.
8. What is the Melting Point?
The melting point is the temperature at which a material changes and goes from solid to liquid. This state change happens because polymer chains fall out of their organized structure, resulting in a disordered liquid.
9. When Does Melting Point Matter?
Understanding a polymer’s melting point can help identify the impact that heat, impurities and fillers have on product performance. Armed with this knowledge, you can alter processes and product composition to ensure the product performs as expected within normal temperature ranges.
10.How Can I Improve My DSC data?
While there are many different ways to gather DSC data, some tools and techniques may not provide everything you need. For instance, differential thermal analysis can measure melting point, but the results generally aren’t reproducible.
Your results can also depend on the specific instrument that runs your samples. After all, the best data comes from highly calibrated equipment with suitable standards, a smooth baseline, and reasonable separation of the sample peak from any noise in the baseline. That’s why your choice of testing lab can have a significant impact on your DSC data.
Innovatech Labs has over 30 years of material analysis experience. Our experts always use the best equipment for every project, and our team is committed to keeping our equipment in top condition. For example, to improve your DSC data, we may try using a larger sample, running the test at a different speed or utilizing specialized testing pans. There are many methods to refine testing results with the right skills and knowledge.
Experience the Benefits of Working with Innovatech Labs
Do you still have questions about DSC testing? Learn more about DSC analysis applications on our blog. You can also contact us directly for answers to your DSC questions or to discuss an upcoming project.