As seen in the enclosed TGA spectrum a weight increase at 330 to 500 C is seen followed by a decrease. I have no idea why this is possible and need some insight. Thank you
Dear Nataie Arnett,
Could it be some chemical reaction involving oxygen absorption by the sample
"Every cloud has a silver lining"! The effect you have observed may be useful for the porous materials (polymer foams) fabrication...
Dear Yongliang Zhao Sir / Serge V Shil'ko Sir,
How can mass increase on heating?
In response to the previous comments:
1. We don't know how the mass is increasing because even if small molecules were being loss the mass should decrease.
2. Additionally a chemical reaction with oxygen absorption is not possible because this was conducted under an inert environment.
3. The negative values at the end of the TGA may be due to the loss of some of the sample when it puffed up in the pan.
We ran the sample again but only to 450 C where a sharp in crease in weight was observed and it seems by rough assessment that the mechanical properties of the polymer improve dramatically at this point. Still confused...
From the shape of the curve it seems that there is a chemical reaction which adsorbs some chemical from the atmosphere being used (Oxygen, Nitrogen etc.). This chemical reaction can be with some of the intermediate/decomposition products.
In my experience this happens if solvent residues are present in the polymer sample.
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