THERMAL-DECOMPOSITION OF POLY(1,6-DI-N-CARBAZOLYL-2,4-HEXADIYNE)

The kinetics of the thermal decomposition of the crystalline poly(1,6-di-N-carbazolyl-2,4-hexadiyne) prepared by gamma-radiation induced polymerisation were studied over the temperature range 380 450-degrees-C by means of a flow system, coupled to a gas chromatograph. Two major volatile reaction products were found: carbazole and 9-methylcarbazole, leaving behind a carbonaceous residue. The reaction was found to be complex with two autoacceleratory regions followed by a very slow limiting rate after 65% weight loss. Whereas the magnitude of the first of these regions was found to be dependent on factors influencing the level of crystal purity and perfection, the second region was independent of these. A reaction mechanism is proposed, based on initiation by stress-induced shearing of sidegroups, followed by concurrent molecular/radical non-chain processes. The kinetics of the decomposition were found to be best described by the Avrami-Erofeyev equation, and the Arrhenius parameters were determined for both autoacceleratory processes.