Synthesis of carboxymethylcellulose/acrylic acid hydrogels with superabsorbent properties by radiation-initiated crosslinking

• CMC/AAc hydrogels were prepared by radiation-induced crosslinking.
• Gelation required lower dose and solute concentration in CMC/AAc solutions.
• Increased AAc concentration improved the gel fraction at the expense of water uptake.
• In mild synthesis conditions CMC/AAc gels had better properties than pure CMC gels.
• Substitution of CMC with AAc up to 10% proved to be the most effective.

Superabsorbent hydrogels were prepared by gamma irradiation from aqueous solutions of carboxymethylcellulose (CMC) and acrylic acid (AAc) with varying CMC:AAc ratio. By partially replacing the CMC with AAc the gelation increased and led to a higher gel fraction and lower water uptake. Moreover, the gelation required significantly milder synthesis conditions. Decreasing both the dose and the solute concentration in the presence of AAc led to gels with higher gel fraction and higher degree of swelling compared to pure CMC gels. Increasing the AAc content up to 10% proved to be very effective, while very high AAc content (over 50%) hindered the gelation process.