Structural and functional characterization of rice starch-based superabsorbent polymer materials

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials

Background:

• Superabsorbent materials (SPAMs) are crucial for various applications, but environmental concerns necessitate biodegradable alternatives.
• Rice starch, an abundant and renewable resource, offers potential for developing sustainable SPAMs.

Purpose of the Study:

• To develop novel, degradable, and eco-friendly superabsorbent materials (SPAMs) based on rice starch.
• To investigate the influence of rice starch composition (amylose/amylopectin content) on SPAM properties.
• To evaluate the performance and reusability of rice starch-based SPAMs.

Main Methods:

• Synthesis of SPAMs using indica and glutinous rice starch.
• Characterization of SPAMs using Fourier Transform Infra-Red spectroscopy (FTIR) and X-Ray Diffraction (XRD).
• Microstructural analysis via Scanning Electron Microscopy (SEM).
• Evaluation of water absorption capacity, water holding capacity, and regeneration rate.
• Assessment of cation effects (K+, Na+, Ca2+, Al3+) on water absorption.

Main Results:

• Indica rice starch-based SPAMs showed the highest water absorption (439 g/g), attributed to high amylose content (23.6%).
• Glutinous rice starch-based SPAMs (75.1% amylopectin) also exhibited good absorption (399 g/g).
• SPAMs demonstrated good reusability, retaining 30% capacity after three cycles.
• Water absorption was influenced by cations in the order: K+ < Na+ < Ca2+ < Al3+.
• FTIR and XRD confirmed graft copolymer formation; SEM revealed a porous microstructure.

Conclusions:

• Rice starch is a viable precursor for developing high-performance, eco-friendly SPAMs.
• Starch composition significantly impacts SPAM water absorption and retention capabilities.
• Indica rice starch-based SPAMs are effective in preventing moisture accumulation in stored rice grains.