Please clarify how you define crystallinity before you compare your samples. if it is by melting point or its enthalpy, your observation is likely caused by the particle size itself, which can affect the measured temperature, etc. of thermal events. You'd better perform xrpd to define crystallinity of your sample.

Dear Sharad,

I have found as being of real interest your question. My first idea was that by grinding, the micro powders will crystallize during DSC heating somewhat not in the same manner as the bigger polymeric pieces, whereas the influence of initial thermal history (ascribed to cryo-milling) can be also for consideration…

To not be wrong in some explanations, let’s go to consider the following paper which is sharing an experience well connected to the subject of your question:

Zhu, Y. G., Li, Z. Q., Zhang, D., & Tanimoto, T. (2006). Effect of cryomilling on the thermal behaviors of poly(ethylene terephthalate). Journal of Applied Polymer Science, 99(6), 2868–2873. doi:10.1002/app.22576

Good luck in your R&D works and best regards,

Marius

Dear Sharad,

The Authors are also on the RG website, so do not hesitate to change information if you have additional questions!

https://www.researchgate.net/publication/237875409_Effect_of_cryomilling_on_the_thermal_behaviors_of_polyethylene_terephthalate

Zhu, Y. G., Li, Z. Q., Zhang, D., & Tanimoto, T. (2006). Effect of cryomilling on the thermal behaviors of poly(ethylene terephthalate). Journal of Applied Polymer Science, 99(6), 2868–2873. doi:10.1002/app.22576

Thank you both for offering some explanation. I will also look into the reference cited.