The granules of polypropylene and metal microparticle compound were feed to melt spinning machin. Differential scanning calorimetry (DSC) measurements were carried out to examine the melting behavior of multifilament yarns. Do you think the attached curve makes sense? What is the cause of the peak at 77 degrees Celsius? Should the test be repeated? The homopolymer is pure and there are no other components in the mixture. (This peak does not exist when the concentration of metal particles is lower)
Dear Elham,
If I’m following well your explanation, the endothermal peak (at about 77°C) is only appearing by adding high amounts of metallic powder in PP. We do not have more experimental details, but I assume that some dispersion additives (stearic acid, waxes of different nature, fatty acid derivates, (co)polymers, others) can be present in your metallic powder.
My first suggestion is to do a DSC and a TGA on your metallic powder, and to use DSC heating-cooling-heating cycles for more information.
Good luck in your R&D study and best regards,
Marius
Dear all, what is the metallic microparticles ? Does it have any possibility on: 1- degradation of PP, and 2- nucleation of crystallization from melting. Neat PP in some cases is known by this double melting. Please have a look at the following link and attached file. My Regards
https://tinyurl.com/mryv48ne
The 77 C peak is obviously not a melting point;
that energy absorption peak may come from crystalline rearrangement or crystallization ( spherulites ) derived from the conditions of the cooling performed on the sample tested.
Dear Marius Murariu and Abdelkader BOUAZIZ
I appreciate for your answer.
Peak at 77°C was not observed when I tested the thermal behavior of metal and polymer separately. I did not use any additives. Compared to the attached curve, the metal concentration increased by only one percent.
Many thanks; Dr. Emilio Malaguti
I agree with you, but in previous articles, a temperature of 77 has never been reported (at least I did not see).
Finally we found out that the DSC instrument needed to be repaired. I did the DSC analysis again. In the new curve, the peak at 77 ° C and the noise observed in the previous curve were removed. Thank you for your cooperation and attention.
Dear Elham,
Not to delay more! Thank you for this information and confirmation that the peak at 77°C in case of PP was in fact,... an experimental artefact.
Good luck in your R&D projects and best regards,
Marius
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