Synthesis of Aromatic Polyamidines by the [2+2]-Cycloaddition Reaction

Aromatic polyamidines based on 4,4′-diphenylmethane diisocyanate and bisamides have been synthesized and studied. The one-step reaction of bisamides with diazocyanate according to the [2+2]-cycloaddition mechanism includes a concerted process of the formation of two new σ-bonds in the transition state. The formation of polyamidine occurs as a result of decarboxylation, which completes this reaction. Due to the availability of starting compounds, ease of synthesis, good solubility, and high heat resistance and thermal stability of the resulting polymers, there are wide opportunities for producing new materials by conventional industrial processes. Polyamidines have a sufficiently large set of important technological properties, which suggest their greater potential in relation to applied problems. The resulting film materials and glass-reinforced plastics based on polyamidines show high mechanical properties that are not inferior to those of materials made from commercial polyamides and polybenzimidazoles.