Modified poly(ethylene‐co‐propene‐co‐1,4‐hexadiene) (EPDM) bearing acetylacetonato groups and its chelate crosslinking with Fe(III)

Abstract

AbstractAcetylacetonato group‐bearing poly(ethylene‐co‐propene‐co‐1,4‐hexadiene) (EPDM) was prepared and its chelate by crosslinking reaction with ferric salts. The hydroiodination of residual double bonds in the EPDM terpolymer under phase‐transfer conditions and the substitution of iodine atoms in the hydroiodinated EPDM by acetylacetonato groups were studied. The ligand exchange reactions of acetylacetone with ferric trifluoromethanesulfonate (Fe(TFS)3) or ferric chloride in THF were explored by UV/Vis spectroscopy to find optimum conditions for the formation of the chelate complex ferric acetylacetonate. The results indicate that these two ligand exchange reactions are equilibrium reactions, and the addition of an organic base such as triethylamine can make the reactions go to completion. The character of the anion in the ferric salts has a significant effect on the ligand exchange reactions, which may be attributed to the different dissociation tendency of FeX bonds. The ligand exchange reactions in the polymer systems were studied, and Fe(III)‐chelate complex crosslinked EPDM elastogels with gel fractions higher than 90% were prepared. The mechanism of the chelate complex formation in the polymer systems is similar to that in model compound systems.