SYNTHESIS OF TETRAFUNCTIONAL EPOXY-RESINS FROM DIAMINES AND EPICHLORHYDRINE

Tetrafunctional epoxydic resins are prepared starting from aromatic di amines 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 positio n. The reaction of epichlorhydrine with these amines shows that desact ivating substituents such as NO2 decrease the kinetics compared to act ivating substituents such as OCH3 or weakly activating substituents su ch as CH3. In a second study, tetrafunctional epoxydic resins were pre pared starting from diamines presenting variable basicity: diamino 4 4 ' diphenyl methane, diamino 4 4' diphenyl sulfone, 4 amino phenyl ethe r and finally, an aromatic amine including an ether link and a perfluo roalky 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 p henyl ether, its low solubility in common solvents prevents conclusion s being drawn about its reactivity. We noted also that products obtain ed after epoxydation are unstable. In theory, the basicity of the fluo rinated 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 gr oup reduces the activating effect.