Akademik Veri Yönetim Sistemi
MATERIALS FOCUS, cilt.3, sa.4, ss.310-317, 2014 (ESCI)
The reaction mechanism of decomposition process and the kinetic parameters of poly(5-hydroxyquinoline) synthesized by oxidative polymerization were investigated by thermogravimetric (TG) analysis at different heating rates. TG curves showed that the thermal decomposition occurred in two stages. The methods based on single and multiple heating rates were used to calculate the kinetic parameters. Compared with other methods based on single heating rate such as the Coats-Redfern (CR), van Krevelen (vK), Horowitz-Metzger (HM), these six methods present the advantage that they do not require knowledge of the reaction mechanism for determining of activation energy. The activation energies obtained by methods based on multiple heating rate such as the Kissinger, Kim-Park (KP), Tang (TM), Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Friedman were found to be 71.9, 75.5, 73.4, 73.1, 74.8, and 74.0 kJ/mol for the first decomposition stage, 498.5, 484.3, 522.1, 521.7, 522.1 and 522.7 kJ/mol for the second decomposition stage, respectively. The mechanisms and pre- exponential factor for each thermal decomposition stage were also determined by CR, vK, HM and master plots. The analysis of the master plots showed that the decomposition mechanism of poly(5-hydroxyquinoline) (PHQ) in N-2 went to the D-6 mechanism for both decomposition stages.