SYNTHESIS OF TETRAFUNCTIONAL EPOXY-RESINS FROM DIAMINES AND EPICHLORHYDRINE

Tetrafunctional epoxydic resins are prepared starting from aromatic diamines and epichlorhydrine. The kinetics of the reaction depend on the basicity fo the amines used. Accordingly a first study was undertaken with monoamines possessing different substituents in the para position. The reaction of epichlorhydrine with these amines shows that desactivating substituents such as NO2 decrease the kinetics compared to activating substituents such as OCH3 or weakly activating substituents such as CH3. In a second study, tetrafunctional epoxydic resins were prepared starting from diamines presenting variable basicity: diamino 4 4' diphenyl methane, diamino 4 4' diphenyl sulfone, 4 amino phenyl ether and finally, an aromatic amine including an ether link and a perfluoroalky line. The products obtained have been characterized by H-1 NMR. It was found;that diamino 4 4' diphenyl sulfone is less reactive than its homologue 4 4' diamino diphenyl methane. In the case of 4 amino phenyl ether, its low solubility in common solvents prevents conclusions being drawn about its reactivity. We noted also that products obtained after epoxydation are unstable. In theory, the basicity of the fluorinated amine should be increased by the ether group in para position. However, we did not observe any increase in reactivity of this amine because the perfluorinated group in the alpha position of the ether group reduces the activating effect.