Synthesis, characterization, conductivity, band gap, and kinetic of thermal degradation of poly‐4‐[(2‐mercaptophenyl) imino methyl] phenol

The oxidative polycondensation reaction conditions of 4‐[(2‐mercaptophenyl) imino methyl] phenol (2‐MPIMP) were studied in an aqueous acidic medium between 40 and 90°C by using oxidants such as air, H 2 O 2 , and NaOCl. The structures of the synthesized monomer and polymer were confirmed by FTIR, 1 H NMR, 13 C NMR, and elemental analysis. The characterization was made by TGA‐DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly‐4‐[(2‐mercaptophenyl) imino methyl]phenol (P‐2‐MPIMP) was found to be 92% for NaOCl oxidant, 84% for H 2 O 2 oxidant 54% for air oxidant. According to the SEC analysis, the number‐average molecular weight ( M n ), weight‐average molecular weight ( M w ), and polydispersity index values of P‐2‐MPIMP were found to be 1700 g mol −1 , 1900 g mol −1 , and 1.118, using H 2 O 2 ; 3100 g mol −1 , 3400 g mol −1 , and 1.097, using air; and 6750 g mol −1 , 6900 g mol −1 , and 1.022, using NaOCl, respectively. According to TG analysis, the weight losses of 2‐MPIMP and P‐2‐MPIMP were found to be 95.93% and 76.41% at 1000°C, respectively. P‐2‐MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P‐2‐MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, and the electrochemical energy gaps ( E ′ g ) of 2‐MPIMP and P‐2‐MPIMP were found to be −6.13, −6.09; −2.65, −2.67; and 3.48, 3.42 eV, respectively. Kinetic and thermodynamic parameters of these compounds investigated by MacCallum‐Tanner and van Krevelen methods. The values of the apparent activation energies of thermal decomposition ( E a ), the reaction order ( n ), pre‐exponential factor ( A ), the entropy change (Δ S *), enthalpy change (Δ H *), and free energy change (Δ G *) were calculated from the TGA curves of compounds. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009