Studies of crosslinked poly(AM-MSAS-AA) gels. I. Synthesis and characterization

Novel superabsorbent copolymers were prepared from acrylamide (AM), sodium methallylsulfonate (MSAS), sodium acrylate (AA), and N,N′-methylenebisacrylamide (BisA) in aqueous solution using potassium persulfate (KPS)/ N,N,N′,N′-tetramethylethylenediamine (TMEDA) as the redox initiator. The copolymers were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The experimental results show that absorbency increases with an increase in crosslinker concentration but decreases with excessive crosslinking. The ionic groups in the polymer network significantly increase the equilibrium swelling. Water retention at pressures of 1-10 kg/cm² and temperatures of 60 and 100°C are also reported.