The thermal decomposition of crystalline poly(1,6-bis-N-carbazolyl-2,4-hexadiyne) was examined by thermogravimetric analysis (t.g.a.) using both isothermal and temperature-programmed methods over a temperature range of 400-600°C. Extents of decomposition versus time data were fitted to an Avrami-Erofeyev equation with the exponent equal to three. Two consecutive processes were observed, each with its own Arrhenius parameters. An independent study, reported by us elsewhere, involving a flow system, leads to results consistent with the parameters obtained by t.g.a, reported in this investigation. Differences in reactivity between polymer crystals prepared by heating and by y-radiation have been noted and discussed. Levels of imperfection of the crystals, determined by the choice of polymerization method, appear to correlate with the observed pre-exponential factors. The numerical value of the activation energy found for the second kinetic regime, which is attributed to the chemical process itself, is consistent with a process of bond breaking at the methylene-carbazole bond being the rate-determining step of the decomposition.
Посилання на статтю:
Analysis of the kinetics of the thermal decomposition of poly( 1,6- b is-N-ca r bazo lyl- 2,4- h exad iyn e ) obtained using thermogravimetric analysis / Friedrich P. Bradner and Jacob S. Shapiro // Polymer. – 1992. – Vol 33. – P. 4366-4374.