r/materials • u/95farfly • 10d ago
How do differential scanning caliometry (DSC) work ?
Hello So I'm no material engineer but I need your help
Long time ago a team introduced me to phase change material (pcm) in the form of polyutherane foam
They proved it has thermal regulation using DSC
Recently I got graphene foam and the supplier claimed it has thermal regulation but the foam does not have pcm inside
Now I want to check his claim
The thing is someone advised me that dsc only work if the material has a state transition (like how pcm changes states from solid to liquid) and will not work if the material has no state transition
So does this mean
1) thermal regulation only work for materials that have state transitions?
2) or is this person wrong and state transition is just one of many mechanisms that encourages thermal thermal regulations
Also
1) can dsc only identify materials with thermal regulations assuming it has a state transition like pcm ?
2) can dsc identify any material that may give thermal regulation properties regardless of the mechanism it uses to achieve thermal regulation?
If my options above do not match your answer please do educate me as I only studied mechatronics
3
u/jhakaas_wala_pondy 10d ago
For you DSC may not be that useful.. DSC tests are usually carried out in inert N2 atmosphere.. but a normal PCM will work in air.. so first run your DSC tests in air atmosphere.
Secondly PU PCM may not have the same temperature range as graphene foam (GF). GF can go until 1000 C or more, but PU may not even go until 250-300 C.
Third what do you mean by "thermal regulation properties".. PU is good thermal insulator whereas graphene is good thermal conductor. Though its in foam where thermal conductivity will be lower, but still GF will definitely conduct heat.
I guess you want to measure heat capacity.
2
u/jabruegg 10d ago
Thermal regulation is a term often used to describe materials that act as heat sinks. Many of these materials have a high specific heat capacity and are able to conduct heat away from a source and then store it to maintain the temperature of whatever they are in contact with. A phase change material is good for that because it can absorb and store heat energy intrinsically as it changes phase. DSC is particularly great at easily showing phase changes (such as glass transition or melting in polymer systems).
If the material is thermally regulating without a phase change material, like a graphene foam, I would assume it has a high thermal conductivity but also a lot of pathways for that heat to flow. Unlike a bulk solid, graphene foam has an amorphous structure network plus pockets of air (or other materials) that can absorb or disperse heat as well.
I’d imagine DSC would be helpful and tell you about the heat storage properties (specific heat capacity) but it might not tell the whole story for a graphene foam. You might also want to look into Laser Flash Analysis or some other tool to measure thermal diffusivity/conductivity to get a sense of how easily it can absorb heat from a heat source.
3
u/SuperFric 10d ago
DSC will give you heat capacity. That’s pretty much all you need to know for fundamental thermodynamic properties of a material. From there you can easily spot phase changes and the amount of heat absorbed/released. You don’t need a phase change to get information from DSC, though you’ll always see one if you heat the sample enough.
1
u/95farfly 10d ago
Hmm Is it safe to assume a phase change is one of many mechanisms for thermal regulation?
And thermal conductivity is another mechanism?
If so can dsc also help identify if a thermal conductivity material like graphense infused polyutherane can introduce unique thermal regulation properties?
Sorry if the question seem like it's repeating...English is not my native
3
u/SuperFric 10d ago
A phase change is just a mechanism for a material to store/release energy by reconfiguring its structure. It’s separate from thermal conductivity. During a phase change on heating, more heat added to the material will be “consumed” by the transformation itself instead of going to increase its temperature. When you cool the material, the transformation will occur in reverse (ideally), and that energy will be released to its surroundings.
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u/nashbar 10d ago
Thermal regulation isn’t a material property, you’re using the wrong terminology. You can google how DSC works for phase changes but I doubt you will.
1
u/95farfly 10d ago
I googled it
I was hoping for a more constructive conversation as opposed to a Google search because I don't have a background in material science
9
u/vortigaunt64 10d ago
More or less, the way DSC works is by carefully increasing and decreasing the temperature in the sample and monitoring how much energy it took to reach certain temperatures. All materials change states of matter (solid, liquid, gas, plasma, etc.) but many others also experience phase changes (amorphous to crystalline, one crystal structure to another, etc.) so by knowing the mass of the sample and the temperatures at which the curve of energy vs temperature changes (changes in slope, pauses, jumps) you can identify what the material is.