Is it possible to convert a crystalline polymer into a non-crystalline (amorphous) polymer by dissolving the crystalline polymer in a heated solvent?
in the DSC thermogram the crystalline polymer lost their melting point (Tm)and kept their glass transition temperature (Tg) in the heating stage, and lost their crystallization peak (Tc) in the cooling step
Dear Mohamed,
please have a look at the answers of a very similar question from some time ago here on RG:
https://www.researchgate.net/post/which_is_most_reliable_method_for_conversion_of_crystalline_compound_in_to_amorphous_form
The seond link might help you too:
http://digitalcommons.uri.edu/cgi/viewcontent.cgi?article=1272&context=theses
Starch is the best example for your answer. When starch in dispersion (water as solvent) heated, gelatinization occurs, and lost its crystallinity and converted to amorphous state.
yes. dissolve the polymer in relevant solvent and heat till it melts and then cool rapidly
Dear gentlemens, thank you for your answer, but how can I explain this result ?, knowing that there are two types of this polymer, a semi-crystalline with Tg of 85C and the other amorphous with Tg of 62C, but I find myself my polymer after dissolution an amorphous polymer with Tg a 81, (the native polymer is semi-crystalline and Tg of 85C)
is it possible to suggest works take this phenomenon of transformation?
Dear Phuong Nguyen-Tri
Thank you Professor for tour explcation
my case is not in polymer blend, but in one polymer native
the DSC thermogram of polymer native (before casting) show a glass transition Tempearature Tg and an melting point Tm (endothermic peak-heating step) and crystallization temperature Tc (exothermic peak-cooling step)
the same polymer after dissolving the DSC thermogram show a same Tg and no Tm and Tc
Dear Mohamed, As mentionned by Phuong Nguyen-Tri, the cristallinity of the polymer depends on many factors, your result is normal, the polymer can lost his cristallinity with solvatation or by fast cooling from his liquid state to a glass state. So your polymer was changed to amorphous one
regards
Hi Mohamed,
When a sample quenched after its melting point, it may convert to amorphous form. But, in your cafe you found some crystallization in cooling, means your sample was not converted to amorphous form. It might be converted to same crystalline or other crystalline form while cooling. But, i don't understand why you dissolved the sample, it may be the reason for conversion to amorphous form.
Dear Srinivasa Rao Kanumuri
Thank you Professor for tour explications
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