FUNCTIONALIZATION OF POLYSTYRENE RESINS BY CHEMICAL MODIFICATION - CHARACTERIZATION OF HALOGENATED POLYSTYRENES BY C-13 NUCLEAR MAGNETIC-RESONANCE SPECTROSCOPY

The halogenation of polystyrene using ferric chloride and thallic acetate as catalysts for the bromination, and thallic trifluoroacetate with iodine in stoichiometric amounts for the iodination, has been studied by 13C-NMR spectroscopy using standard polymers obtained by polymerization of o-, m-, and p-bromostyrene. In all cases, the halogenated polymers were found to be substituted exclusively in the para position. Similarly, a brominated polymer prepared by reaction of polystyrene with n-butyllithium-TMEDA complex followed by bromine quenching was found to be substituted exclusively in the para position, while a similar lithiation followed by quenching with methyl iodide gave a methylated polymer substituted both in the meta and para positions in a 2:1 ratio. Lithiations carried out with tert-butyllithium-TMEDA resulted in higher degrees of functionalization than those carried out with n-butyllithium-TMEDA. © 1979, American Chemical Society. All rights reserved.