Synthesis and characterization of new polyesters containing imidazolidine-2,4,5-trione rings

New polyesters containing both aliphatic and aromatic units in the backbone were prepared by the reaction of 4,4′-[hexane-1,6-diyl bis(2,4,5-trioxoimidazolidine-1,5-diyl)]dibenzoyl chloride (2) with various biphenols (4a–4f). A model compound diethyl-4,4′-[hexane-1,6-diyl bis(2,4,5-trioxoimidazolidine-1,5-diyl)]dibenzoate (3) was synthesized by the reaction of monomer (2) with ethanol. Monomer (2), model compound (3) and polymers (5a–5f) were confirmed structurally by IR and 1H-NMR spectroscopy and characterized by their viscosities, solubilities and thermal properties. A liquid crystalline behavior in the melting state was noticed for polymers containing hydroquinone (5a) and 1,5-naphthoxy (5b) units in the backbone.