The endothermic curve starts at a temperature of 30°C itself. Peaks vary for both the AEM and HNBR compounds. The peak for AEM is at 50.2°C and for HNBR is at 123.25°C. The enthalpies vary enormously. For AEM it 1.139 J/g and that for HNBR is 18.34 J/g. Also I dont find these peaks with the peroxide cured AEM and HNBR compounds.
Please find DSC scans of the diamine cured AEM and HNBR materials in the attachment.
I would like to understand as to why these endothermic peaks are occuring.
I thinks its a good question from Mike Hale.
Have the samples been annealed before measurement?
Are there any waxes in the compounds, especially in AEM?
If possible, do a TGA as well. This will give you an idea if there are any mass loss and where it occurs.
Otherwise reweigh the pans after the DSC experiment.
Thank you for all of your answers.
Mike Hale To check if the cures are reversible I have not performed the 1st cooling. And yes it is a good point that it might be the loss of volatiles as well. I will come back to you regarding this.
Matthias Jaunich The samples have not been annealed. It was directly tested on DSC. I am not sure if they are waxes present in the compound but surely we have added TOTM plasticizer in the compound. Would you be linking this to the volatile evaporation what Mike Hale suspected?
Abrie Myburgh I have also performed the TGA for HNBR compound. Please find the same in the attachment. The blue curve is from the HNBR compound. Rest all curves are aged in differetn conditions. In TGA I do not find a mass loss at just 30°C. But in the DSC the enodtherm starts from roughly around 30°C. So I am too suspecting this of any volatile evaporation but I am also thinking how could the volatile evaporation go on until 150°C in case of HNBR and only upto 50°C for the AEM compound. Also as you mentioned I would like to try this out by weighing the pans before and after the test. This can also confirm for the volatile evaporation.
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