I'm seeing a very shallow and a broad peak ranging from 100 C to onset of melting in DSC of glass fiber filled PPS. TGA shows no volatile. It is also not a re-crystallization peak which normally is very sharp and at 120-125 C for PPS. PPS is not hygroscopic and is thermally stable up to 260 C. What causes such peak? Is it related relaxation of thermal stresses in sample?
Also, what causes the crystalization peak to have a shoulder (kind of a second peak).
I have attached DSC scan.
It could be a glass transition with a hysteresis peak , I checked, and the Tg for the PPS is around 85°C. How is the fusion peak ?
It is not Tg. It is a broad peak ranging from 100 C to 280 C with 3-8 mj/mg enthalpy. I think, it has something to do with sample relaxing. But not sure.
I didn't explaint it well, I meant that amorphous polymers usually shows a endothermical hysteresis peak due to relaxation after Tg (in heating experiments), such as in PET.
Maybe this paper could help you:https://www.sciencedirect.com/topics/materials-science/enthalpy-relaxation
Regards.
- Badges
- Science topic
- Similar topics
- Engineering
- Petroleum Engineering
- Gas