I want to know the formula to find the crystallinity of a polymer blend using DSC . As the sample is amorphous in nature, so we won't get the crystallization peak.
In DSC, generally you observe a crystallization peak or a melting peak of semi crystalline polymers.
As said Antonio, you need a reference of DH value for calculating the cristallinity. But if your polymer can not crystallize, you won't observe these peaks.
But sometimes, the presence of fillers (as you are talking about polymer blends) facilitates to crystallize the polymers.
No cristallization peak in DSC, no cristallinity calculation of polymer by DSC.
Dear Subhankar,
You say "A typical polymer blend have small molecules which would show neither a glass transition nor a crystallization peak".
What do you mean by saying "typical polymer". It can be amorphous or semicrystalline. Which one is typical? Why it will not show a crystallization peak if it is semicrystalline and can crystallize more? You can obtain the melting peak only if the polymer posseses the crystallized domains. If a semicrystalline polymer has initially an amorphous structure, during heating it will not give a melting peak. Only the crystallized zones will give you the melting peak.
Dear Dr.Subhankar,
I thank you for your comments.
I agree with you if you are talking about the low molar mass polymers which have less chance to crystallize compared to long chains polymers .
If we are looking for the actual crystallinity of a polymer, it can be calculated from the melting peak in DSC, as you mentioned. If we are looking for the maximum crystallinity (which polymer is able to have) of the polymer, one way to do is the "crystallization from melt". This is why I told about the crystallization peak (-> I should say crystallization peak from melt).
I just would like to say that if there is no melting peak,"at the actual state of polymer", this means that the polymer doesn't have the crystalline domains. But this doesn't mean that the polymer can not be crystallized.
I also insist that the presence of filler can modifiy the crystallization process in polymer blends.
I thank you again for your reply Dr. Subhankar.
Best regards
Actually, I need a similar solution for my problem. Because I need to calculate crystallinity in my blends. This calculation can be made easily in pure polymers or mono polymeric nanocomposites. But I couldn't find any calculation example in the blends which composed with two different polymers. Thanks for your answer and solutions.
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