Abstract1. Polyfunctional isocyanates, insoluble in the common solvents, have been prepared by acid as well as by alkaline phosgenation of a solid polyamino‐polystyrene. The light brown powders are identical in appearance with the starting material; they exhibit, however, a strong sharp IR.‐absorption band at 2260 cm−1(4.43 μ), and show no absorption peaks due to the presence of primary amino