Crosslinked DADMAC polymers as cationic super absorbents

摘要

Loosely crosslinked cationic polyelectrolytes (polyquats) with super-water-sorption abilities are presented, for the first time. Hydrogels obtained by radically initiated copolymerization of N,N-diallyl, N,N-dimethyl ammonium chloride (DADMAC) with N-vinyl 2-pyrrolidone (NVP) in presence of N,N,N',N'-tetraallyl piperazinium dichloride (TAP) as crosslinker showed reasonably high equilibrium swelling ratios, as high as those for poly(acrylic acid)-based super absorbents.rnThe highest swelling ratios (up to 360) were attained by fully cationic hydrogels derived from DADMAC and 0.5% TAP. The hydrogels with 0.5-5% crosslinkers exhibited rapid expansion in neutral water, so that the equilibrium swelling values were attained within 2-3 min. The crosslinking densities of the gels were estimated by Flory-type swelling model using "phantom network elasticity" for the elastic contribution. This estimation revealed low crosslinking efficiencies of TAP (0.24-0.35) due to its double cationic charge.rnIn the study "the salt effect" and effects of the comonomer ratios and crosslinker contents on the swellings were also investigated.