Effect of polymeric structure on Tg

The physical properties of a polymer are determined to a large e.xtent by the chemical structure. The thermal morion of the polymer chains is dependent on the ability to rotate around the main chain. This is mainly determined by two factors  

Tabic 11.5 Glass iran.siiion icmpcraiurc of variou.s polymers 4J 

In order to correlate the structural parameters of a polymer to its permeability 

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