Preparation and thermal decomposition kinetics research of pyridine-containing polyimide

The synthesis and thermal research of a pyridine-containing polyimide were reported in this work. The corresponding diamine monomer, 2,6-bis(4-(4-aminophenoxy)phenyl)-4-phenyl pyridine (BApPP), was synthesized through combining the nucleophilic aromatic substitution with modified Chichibabin reaction and hydrazine monohydrate reduction. Fourier transform infrared spectroscopy (FT-IR), 1 H nuclear magnetic resonance spectroscopy ( 1 H-NMR), and elemental analysis were used for chemical structural characterization, the results identified the chemical structures of the monomer and polymer. The melting behavior of the diamine monomer was studied by differential scanning calorimetry (DSC). The thermal properties of the resulting polyimide were investigated from DSC and thermo gravimetric analysis together. The results indicated the resulting polyimide exhibited excellent thermal stability, with the glass transition temperature around 275.0 °C and the initial mass loss of sample beyond 487.5 °C. The thermal decomposition process was analysed by combining the Avrami–Erofeev dynamic model and Ozawa–Flynn–Wall method. The coefficients of the thermal decomposition kinetics equation were calculated, and the final equation was obtained by polynomial fitting method.