[Maryna]

We are trying to measure melting temperature of a polypropylen-polyacrylic acid block-copolymer. Reference melting temperature is 170°C, but we observe a small peak at 80°C, and after that there is a flat line up to 300°C. Can't explain a straight line DSC graph. What may go wrong? Thanks.  Maryna

[jeffmoonchop]

could be rearranging itself to a more stable form before the new form melts. 80 may be the temperature required to allow it to rearrange or degrade.

[P]

I would have to agree that it sounds like a phase change or a Tg.

[jeffmoonchop]

if it is a phase change, to figure out the melting point of the initial phase ramp the temperature up very quickly. This will not give it time to change phase but will melt with a broad peak around your desired lit temperature.