I have heat treated and UV exposed PVA films which significantly varied the Tg and mechanical properties. However, I am unable to co-relate any relation between these two. Is there any explanation how Tg can effect mechanical properties?
Md Musavvir Mahmoud,
I expect the heat treatment and UV irradiation has changed the polymeric structure of your samples.
There could be possible degradation or cross linking which will either increase or decrease your Tg and also decrease or improve mechanical properties.
There is a direct effect of the treatment process on the structure of your polymer and therefore on the thermal and mechanical properties such as Tg and stress/strain of your polymer.
I suggest you check the FTIR or NMR of your polymer to investigate how the structure has been affected.
Dear all, Tg is a threshold temperature that indicates a transition from a rigid-brittel-elastic polymer to a flexible-soft-viscoelastic polymer. So, for the same polymer you will get a different mechanical properties whether you are testing below or above its Tg. Exemples, PS at room-temperature is far below its Tg, it behaves as an elastic rigid solid (within a certain range ofcourse), however PE and PP show the opposite since they are far above their Tg's at room-temperature. My Regards
Please see the references below:
DOI: 10.1080/03602559508012202
DOI: 10.1080/03602559808006919
Best Regards
Without more details on what you have done, for both treatments and testing, no answer is possible. But keep in mind that glass transition is not a fixed temperature. It is dependent on speed of deformation in mechanical tests.
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