This work describes the synthesis and macromolecular reactions of citraconic anhydride (CA)acrylamide (AAm) binary reactive copolymers with gamma-aminopropyltriethoxysilane (APTS) as a polyfunctional crosslinker. Copolymers with given composition of poly(CA-alt-AAm) were synthesized by radical binary copolymerization with benzoyl peroxide (BPO) as an initiator in benzene at 70degreesC in nitrogen atmosphere with initial monomer ratio 1: 1. It was shown that the network structure is formed in poly(CA-alt-AAm)/APTS in water by intermolecular reactions between the anhydride unit and the amine group, as well as between the ethoxysilyl fragment and free carboxyl groups of the CA unit and amide unit of AAm. Swelling parameters such as beginning time of the hydrogel-formation, initial rate of the swelling, swelling rate constant, equilibrium swelling and equilibrium water content were determined for the copolymer/APTS/water system with certain (2.75: 1) copolymer/crosslinker ratio. Formation of a hyperbranched network structure through the fragmentation of side-chain reactive groups in studied systems was confirmed by Fourier transform infrared spectroscopy (FT-IR) method. Copyright (C) 2004 John Wiley Sons, Ltd.