Acrylic copolymers with varying degrees of crosslinking (2-20% DVB) based on ethyl acrylate:acrylonitrile:divinylbenzene (EA:AN:DVB) and ethyl acrylate:vinyl acetate:divinylbenzene (EA:VAc:DVB) have been chemically modified through aminolysis reactions with ethylenediamine and hydrazine hydrate to obtain weak base anion exchange resins. The bead copolymers were synthesized by radical suspension polymerization in aqueous suspension copolymerization technique of the monomers in the presence of toluene as diluent. These copolymers were characterized by toluene and methanol uptake coefficients. The reactions of EA:AN:DVB and EA:VAc:DVB with H2N-(CH2)(2)-NH2 and H2N-NH2 center dot H2O led to acrylic resins with good values of weak base exchange capacities. The anion exchangers synthesized were characterized by volume weight, volume and weight weak base exchange capacities, water uptake, IR and UV-Vis spectroscopies and thermogravimetry. The acrylic resins with hydrazide functional groups were found more stable compared to those with amidoethylenamine groups. Both weak base anion exchangers synthesized have good values for the immobilization yields of the aminoacylase but at pH 3.0 the optimum behavior of the immobilized aminoacylase was obtained only for the resin with hydrazide groups. (C) 2005 Elsevier B.V. All rights reserved.