This work describes the synthesis and macromolecular reactions of maleic anhydride (MA)-acrylic acid (AA) binary reactive copolymers with gamma-aminopropyl-triethoxysilane (APTS) as a polyfunctional crosslinker. Copolymers with a given composition of MA-AA (47.17-52.83 wt %) were synthesized by radical binary copolymerization with benzoyl peroxide as an initiator in p-dioxane at 70degreesC in nitrogen atmosphere and initial monomer ratio of 1 : 1. It is shown that the network structure is formed in MA-AA/APTS in water by intermolecular reaction between the anhydride unit and the amine group, as well as between the etoxysilyl fragment and free carboxyl groups of the acrylic acid and maleic anhydride unit. Swelling parameters such as beginning time of hydrogel formation, initial rate of swelling, swelling rate constant, equilibrium swelling, and equilibrium water content were determined for copolymer/APTS/water systems with various copolymer/crosslinker ratios. Formation of a hyperbranched network structure through the fragmentation of side-chain reactive groups in the studied systems was confirmed by FTIR, TGA, and DSC methods. (C) 2003 Wiley Periodicals, Inc.