Preparation and Properties of Poly(enaryloxy nitriles) Containing Schiff Bases

Poly(enaryloxy nitriles) containing Schiffbases were prepared by reacting p-bis(1-chloro-2,2-dicyanovinyl)benzene (2) with p-hydroxybenzaldehyde, which were then polymerized with various aromatic diamines. The chemical structure of the polymers was confirmed through syntheses of their corresponding Schiff base-containing model compounds. All the polymers were soluble in polar aprotic solvents such as DMF, DMSO, DMAc, and NMP. Moderate molecular weight polymers possessing M w in the range 11 000-21 000 were obtained, and brittle films were cast from DMF solution. They showed a large exotherm around 340 °C attributable to the chemical changes of the dicyanovinyl group. Especially, curing of the azomethine group was observed to occur at 390 °C by differential scanning calorimetry. According to the thermogravimetric analyses, the polymers exhibited excellent thermal stability with 80-95% residual weight at 500 °C under nitrogen.