Carboxylated nanocellulose foams as superabsorbents

Area of Science:

• Materials Science
• Biomaterials Engineering
• Sustainable Chemistry

Background:

• Carboxylated nanocellulose fibers can form superabsorbent foam structures.
• Foam performance is tunable by adjusting process variables.

Purpose of the Study:

• To investigate the superabsorbent capacity of nanocellulose foams.
• To correlate foam structure and properties with processing conditions.

Main Methods:

• TEMPO-oxidized cellulose nanofibres were prepared from hardwood kraft pulp.
• Foams were fabricated using a two-step freezing and lyophilization process.
• Absorption capacity for water and saline solutions was measured.

Main Results:

• Optimized nanocellulose foams (0.3-0.5 wt%, 1.2 mmol/g carboxylate, frozen at -86°C) absorbed 120 g/g H2O.
• Foam pore structure and absorption capacity were influenced by fiber content, charge density, and freezing rate.
• Saline absorption (60 g/g) was lower than water absorption but comparable to commercial polyacrylic acid superabsorbent polymers.

Conclusions:

• Nanocellulose foams exhibit tunable superabsorbent properties.
• These foams are promising renewable alternatives for superabsorbent applications.
• This research contributes to reducing reliance on plastic-based superabsorbent materials.