Glass Transition temperature

i$.$ What is the difference between first order and $2$nd order phase transition?

ii$.$ Write down the various methods of determining glass transition temperature.

iii. Write down the various factors affecting $Tg.$

iv$.$ Why do we need to know $Tg?$ What softening temperature? What is the $Tg$ of a

composite of two different polymers of different Tgs$?$

v$.$ Write the various correlations available for $Tg$ and $Tm$ of polymers?

vi$.$ A PS sample is split into two, and the $Tg$ of each sample is measured by DSC in

two labs. The reported results are $98oC$ and $106C.$ What are the reason for

dissimilar results?

vii. Di$-$ n$-$ethyl phthalate $($DEHP$)$ is used to plasticize PVC$.$ What fraction of DEHP

should be added to PVC to bring $Tg$ down to $27C.$ Tg of DEHP and PVC are $-$

$86C$ and $87C.$