Synthesis of charged linear and crosslinked maleic diester polymers with electron‐beam irradiation

Series of maleic mono‐ and diester monomers have been prepared by esterification of maleic anhydride with poly(ethylene glycol) having different molecular weights, and with n ‐dodecyl alcohol. These monomers were copolymerized with 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) using different dose rates of electron‐beam irradiation ranging from 40 to 150 kGy. The synthesized copolymers were characterized by IR and 1 H NMR analysis. Their aggregation behaviour and viscometric properties in aqueous solutions were investigated. The crosslinked copolymers were prepared in aqueous acidic solutions at pH 1 or in the presence of 1% of N,N ‐methylene bisacrylamide (MBA) as crosslinking agent. The final equilibrium water content and swelling capacities for the prepared hydrogels were determined in aqueous solutions at pH = 1, 6.8 and 12 at 298 K. Swelling equilibria for the prepared hydrogels were carried out in aqueous solutions of NaCl, KCl, CaCl 2 , Na 2 SO 4 , K 2 SO 4 and CaSO 4 at concentrations ranging from 1 × 10 −6 to 2 M at 298 K.