Abstract: The invention provides a water swellable, water-insoluble polymer comprising units derived from a diallylic quaternary ammonium salt monomer cross-linked by a suitable polyfunctional vinyl compound, at least a substantial proportion of the function groups being in basic form. The invention also provides a process for the production of a water-swellable, water-insoluble polymer which comprises polymerising a diallylic quaternary ammonium salt monomer and a suitable polyfunctional vinyl compound as cross-linking agent by cationic polymerisation in an aqueous phase using a free radical catalyst and polymers obtainable thereby. The water absorbent polymers are superabsorbents having improved water absorption properties particularly in respect of saliva solution.

Abstract: The invention relates to a cationic polysaccharide, preferably in fibrous form, having superabsorbent characteristics. The polysaccharides are substituted by quaternary ammonium groups, have a ds of at least 0.5, preferably 0.5 to 2.5 and are cross-linked to a sufficient extent that it remains insufficient in water. The polysaccharide is preferably cellulose. An increased number of functional groups in the product improves superabsorbent properties, whereas use of a cross-linking agent makes it possible to control the gel strength of the product and makes it easier to tailor the characteristics of the product to those which are required.

Abstract: A process for the preparation of aromatic urethans by reaction between aromatic amines and alkyl carbonates, said reaction being carried out in the presence of a catalyst composed of an alcoholate of an alkali metal or an alkaline earth metal. The reaction is caused to take place at a temperature which is variable from +50.degree. C. and +150.degree. C., in the liquid phase and with a molar ratio of the carbonate to the amine of from 10:1 to 1:10.