Synthesis of the superabsobents enriched in chitosan derivatives with excellent water absorption properties

The superabsorbent polymers (SAPs) containing up to 30% w of N-succinylchitosan and N-maleoylchitosan were successfully synthesized by free radical polymerization in an aqueous solution. The structures and surfaces of the synthesized SAPs were characterized by FTIR and SEM, respectively. The influence of the parameters such as type and content of polysaccharide, cross-linker, and comonomer mixture content on the swelling rate was researched. The chitosan-derivative-based SAPs have a higher swelling rate compared to chitosan-based SAPs. Equilibrium swelling rate, Q(e), of the synthesized SAPs lying in the range 102-1144 g/g decreases with the rise of polysaccharide content. It was found that N-succinylchitosan-based SAPs are characterized by higher Q(e) values compared to N-maleoylchitosan ones. The highest swelling rate (Q(e) = 1144 g/g) was achieved for N-succinylchitosan-based polymer containing 2% w of N-succinylchitosan, 0.5% w of cross-linker, and acrylamide-acrylic acid weight ratio was 1:3. Researching the swelling kinetics shows equilibrium swelling is reached during 0-30 min for all synthesized polymers, and equilibrium reaching time rises with the increase in polysaccharide content. Also, swelling is correctly described by the pseudo-second-order model and controlled by chemical absorption of water molecules. The synthesized eco friendly SAPs enriched in polysaccharide content are characterized by excellent water-absorbing properties.

Automated summary

The study showed that superabsorbent polymers based on N-succinylchitosan have a higher water absorption rate compared to those based on N-maleoylchitosan, and the equilibrium swelling rate decreases with the increase in polysaccharide content.