I am not getting fully cured epoxy resin. As the result which I was expecting for Tg is not upto the mark.
You can determined it by DSC or TGA analyses. Please you see files
Okay Sir, I will go through it. But I have one more thing in mind, if we find amine value or free hydrogen content for the cured resin we can get number of primary or secondary hydrogen left unreacted. And so we can also know extent of curing. The problem is how to find amine value for cured film. Can you suggest me some way?
Check out a lot of the papers in my profile for how to do some stochiometric curing. I suppose you are working with stochiometric amounts of Isophorone diamine + polyetheramine (Jeffamine?) to the epoxide equivalent weight. Also, what is your cure cycle like? You might not be curing at a higher enough temperature.
You will need to calculate the amine hydrogen equivalent weight of your hardener mixture and then go to stochiometric amounts with your epoxy once you have that number.
Best way to check for degree of cure quickly is a modulated DSC and look at non-reversible exothermic transitions above where you expect the glass transition to be. Alternatively you can try a FTIR-ATR and look for disappearance of your epoxide peak at ~916 cm-1
Finally, depending on your polyetheramine molecular weight and how many arms your Tg might actually just be really low or influenced by bound water from the environment. Introduction of polyether chains could increase hydrophilicity and this can also result in lower glass transition temperatures.