Hi I was wondering if anyone could help with the interpretation of this DSC curve obtained for PLA powder. I'm unsure as to why there is a peak located at 113.9C. Most of the curves I see in literature show an exothermic event.
The powder is being used used for additive manufacturing, with the addition of a filler, the powder is very prone to warping even when processed at temperatures close to the onset of melting. I believe that this is linked to stresses caused by crystallization, but from the DSC it shouldn't be crystallising at the temperatures im processing it at. If anyone can enlighten me as to what might be occurring i'd be really grateful!
For PLA, mostly Tm is around 160-170C although it depends upon molecular weight and Tg varies between 40 to 60C whereas the temperature you mention I believe it is for the crystallization.
I do support the responses from Ahmed and Dharan. In my opinion I also highly believe the peak obtained is the crystallisation. You can check it further by integrating the curve around that temperature. And I hope you did not obtain the PLA powder curve with the additives involved
Hi! I agree with Dharan. I also think there is a small amount of lactide.
Thank you very much to you all for the replies. I'll perform another scan but use a fast cooling rate to quench the sample from melt, to ensure it all amorphous and then reheat to see if the peak appears again. So is the peak endothermic peak that I'm seeing at around 113C possibly due to the melting of the crystallites?
I had similar case on my molecule.
Based on multiple analyses, I assume that the peak would be a transition peak from a crystalline to another crystalline, a polymorphic form to a single crystalline, hydrated to dehydrated, solvated to desolated, or impurities. Mostly, I agree with phase change of lactide in the polymer.
hye, what if double peak at exothermic but the material is inorganic salt hydrate? why this happen?
- Badges
- Science topic