Chemical-Structure Dependence of Glass Transition

The factors of chemical structures that are related to polymer glass transition behaviors can be classified into two categories, separately corresponding to the intrinsic and extrinsic levels described in Chap. 2. 

The first category is the dominant factor for the glass transition temperatures  

When polymer chains are more rigid, the values of Tg are higher  

So far, how to make a feasible and unified interpretation to the structural dependence of glass transition temperatures above is still a big challenge. 

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