Abstract
Relatively little work on the preparation and reactions of polymers bearing ketonic groups having been reported, the present investigation was designed to determine the ease with which such polymers could be prepared both by polymerisation of ketonic monomers and by the introduction of ketonic groups into the pre-existing polymers, and to conduct a qualitative estimation of the relative reactivities of the ketonic groups when attached to a polymer chain. A series of polymers and copolymers bearing ketonic side-groups has been prepared. Poly(vinylacetophenone) was obtained by the Friedel-Crafts acylation of polystyrene, up to 85% conversion of the styrene units into vinylaceto-phenone units being effected. Several other polymers bearing ketone groups were prepared by polymerising and copoly-merising suitable monomers, including benzylideneacetone, furfurylideneacetone, vinyl laevulinate, 2-cyclohexenone and (+)-carvone. Usually a reactive non-ketonic co-monomer such as styrene, acrylonitrile or maleic anhydride was employed. Benzylideneacetone and furfurylideneacetone were homopolymerised by cationic means, the polymerisation route also involving a condensation reaction of the carbonyl group. 2-Cyclohexenone was satisfactorily homopolymerised by an anionic mechanism; the resulting polymer was shown to be partially microcrystalline, and helical conformations are inferred for the molecules. The preparation of the oxime derivatives of the polymers proved a facile reaction and was used for a qualitative comparison of the reactivities of ketonic polymers. The reactivity of poly(vinylacetophenone) was studied in detail, many of the known reactions of methyl ketones being applied to this polymer. Of these, bromination proved notably useful, the product poly(vinyl-phenacyl bromide) readily undergoing substitution reactions by means of which it was possible to introduce substituents as side-groups to the polymer chain.