Thermal degradation studies of poly(o-anisidine) doped with 5-sulfosalicylic acid

Thermal decomposition of the solid state of poly(o-anisidine) (POAN) base (POAN-EB) and salt [doped with 5-sulfosalicylic (SSA) acid] (SSA-doped POAN) forms has been studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) under non-isothermal conditions. The potential (PE) and optimum molecular geometric (OMG) energies of the repeating unit (tetramer form) of investigated matrix were calculated using molecular mechanics (MM+) calculations. These calculations (PE= -3.48x10(9) and OMG=-122.72 kJ mol(-1)) indicate that the optimum molecular geometric structure of this matrix is highly stable. The empirical formula of the doped polymer is best represented by [POAN-2SSA.n/6H(2)O] and substantiate by elemental analysis and MM+ calculations. The full polymer decomposition and degradation were found to occur in three stages during the temperature increase. The decomposition activation energy (E (d)) of both POAN base (POAN-EB) and its doped (SSA-doped POAN) were calculated by employing different approximations. The heating rate of decomposition and the frequency factor (k (o) ) as well as kinetic parameters were calculated for doped or base form of this matrix. A remarkable heating rate dependence of the decomposition rate of the SSA-doped POAN matrix was observed.