Phthalocyanine polymers. III. Poly(nickel phthalocyanine)benzimidazole as a novel high‐temperature‐resistant polymer

Abstract

A new type of poly(nickel phthalocyanine)benzimidazole was prepared by the condensation reaction between nickel (11) 4,4′,4″,4″′-phthalocyanine tetracarboxylic acid dihydrate and 3, 3′-diaminobenzidine. The reaction was investigated by both the melt and solution condensation methods. This polymer showed good thermal and thermo-oxidative stability. Also noteworthy is its high thermal stability with a char yield of 88% at 800°C in nitrogen. No catastrophic decomposition was observed up to 1100°C. A qualitative study of decomposition in both air and nitrogen is presented. Elemental analyses agreed well with the proposed structure. Infrared (IR) and thermogravimetric analysis (TGA) studies were performed to characterize this polymer, and isothermal gravimetric analysis was done to determine its long-term thermal stability. The apparent activation energies for the thermal degradation in air and nitrogen are given.