Comparison of Major Polymer Types

8 COMPARISON OF MAJOR POLYMER TYPES 7.8.1 Molecular Conformation 

Typically rigid-rod systems such as the aromatic polyamides or the poly-heterocyclic polymers do not exhibit a glass transition, because their amorphous fraction is negligibly small, and they decompose before their melting temperature. By comparison, many of the crystalline random coil polymers, such as the aliphatic nylons, exhibit normal melting phenomena, as well as glass transitions. Thus the properties of the new rigid-rod polymers are quite different from those of random coil polymers. 

Property Rigid Rod Extended Chain Random Coils 

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