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RESEARCH PRODUCT

Synthesis, characterization and thermal degradation of 8-hydroxyquinoline–guanidine–formaldehyde terpolymer

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Abstract Terpolymer (8-HQGF) has been synthesized using the monomers 8-hydroxyquinoline, guanidine, formaldehyde in 1:1:2 molar proportions. The structure of 8-HQGF terpolymer has been elucidated on the basis of elemental analysis and various physicochemical techniques, i.e. UV–Visible, FTIR–ATR and 1 H NMR spectroscopy. Detailed thermal degradation study of the new terpolymer has been carried out to ascertain its thermal stability. Thermal degradation curve is discussed which shows two decomposition steps (265–475 °C and 540–715 °C). Sharp–Wentworth and Freeman–Carroll methods have been used to calculate activation energies and thermal stability. The activation energy ( E a ) calculated by using the Sharp–Wentworth (21.98 kJ/mol) has been found to be in good agreement with that calculated by Freeman–Carroll (23.57 kJ/mol) method. Thermodynamic parameters such as free energy change (Δ F ), entropy change (Δ S ), apparent entropy change ( S ∗ ) and frequency factor ( Z ) have also been evaluated on the basis of the data of Freeman–Carroll method. The order of reaction ( n ) is found out to be 0.9979.