Quantum chemical PM‐3 study of the thermal stability of heterocyclic fragments of heteropolymers, 1. Five‐membered heterocycles: Azoles and imides

Abstract

SUMMARY:Semiempirical PM-3 calculations of the mechanisms of the decomposition of oxazole and maleimide have been carried out. It has been shown that thermal decomposition of the considered heterocycles proceeds via a consecutive breaking of two ring bonds, the breaking of the second bond being the rate-determining step. Both an activation barrier of heterocycle decomposition and its dissociation energy (ED) can be used as a measure of heterocycle thermal stability. The correlation between ED values of azole and imide containing model compounds and the initial degradation temperatures of corresponding heteropolymers makes it possible to clarify some essential features of the thermal degradation of polyazoles, polybenzazoles and polyimides.

Poly(1,6-heptadiyne)-Based Materials by Metathesis Polymerization

“…π-Conjugated polymers such as polyacetylene, − polyacetylene derivatives, − poly(aromatic vinylenes), − polyaromatics, − polyazines, − and polyazomethine, − etc., have been extensively studied for the past 4 decades. Polyacetylene and its derivatives may be conceptually defined as the linear polymers having a π-conjugated system in the main chain.…”