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Specialty Chemistry Forums => Materials and Nanochemistry forum => Topic started by: tati on June 14, 2016, 09:57:03 AM

Title: Polymorphs
Post by: tati on June 14, 2016, 09:57:03 AM

Hello everyone

Does anyone know how the melting point of polymorphic mixtures behave? By melting point, I refer to conventional melting point measurement (capillary) not DSC.

In addition, any good book related to polymorphs?

I guess it is a very specialized question, by any ideas where to look for the answer are more than welcome!

Title: Re: Polymorphs
Post by: jeffmoonchop on June 14, 2016, 10:06:36 AM

if you use a capillary you wont know if heating the sample will cause it to change to another polymorph before it melts. Therefore it is better to use DSC, TGA so you can see that only a melt is occuring and not a phase change before it. If it does change polymorph before melting you will have the melting point of the second polymorph not the first. To find the melting point of the first polymorph you may need to ramp the temp up quickly so it melts before it has chance to change phase, but this is only a rough guide.

Title: Re: Polymorphs
Post by: tati on July 06, 2016, 02:09:52 AM

Thank you for your answer jeffmoonchop.