Fabrication of Eco-Friendly Superabsorbent Composites Based on Waste Semicoke

A series of novel superabsorbent composites of poly(acrylic acid)/semicoke were prepared by polymerization of acrylic acid using ammonium persulphate as initiator, N,N′-methylenebisacrylamide as crosslinker and semicoke which was the by-product of coal carbonizing as the inorganic components. FTIR and SEM analysis indicated that the superabsorbent composites had been successfully polymerized and the semicoke participated in construction of the 3D polymeric network. Meanwhile, the effects of initiator, crosslinker, semicoke, and neutralization degree, as well as the pH value, were investigated, and the results showed that superabsorbent composites containing 10% of semicoke possessed the maximum water absorbency of 584 g/g in distilled water and 75 g/g in 0.9% NaCl solution. The superabsorbent composites kept the high water absorbency within a wide pH range of 4–11, and still exhibited better re-swelling capability even after seven times. The superabsorbent composite with its excellent performance is a potential water-retaining agent used in agriculture.

Superabsorbent polymer composites derived from polyacrylic acid: Design and synthesis, characterization, and swelling capacities

Superabsorbent polymers (SAPs) were synthesized by aqueous solution polymerization of carboxymethyl cellulose (CMC)/acrylic acid (AAc) and polyvinyl alcohol (PVA)/AAc blend using benzoyl peroxide as an initiator. SAPs were synthesized by a facile method under mild conditions. A comparative study was done between CMC/AAc as a biodegradable superabsorbent and PVA/AAc copolymer. The effects of cross-linking, reaction time, temperature, and initiator molar ratio on water absorbency were studied herein. The highest swelling capacity was obtained for CMC/AAc biodegradable superabsorbent composite. The water absorption capacity of SAPs increased with increases in benzoyl peroxide content, immersion time, and reaction temperature of polymerization. The gel fraction of SAPs decreased with increases in the amounts of N, N′-methylenebisacrylamide as a cross-linker. Fourier-transform infrared spectroscopy was used to examine the molecular interactions. The morphology and structure of superabsorbent composites were investigated by scanning electron microscopy.

Ultraviolet-induced polymerization of superabsorbent composites based on sodium humate and its urea release behavior

This study was carried out to develop a superabsorbent composite for agriculture application, which is based on acrylic acid and sodium humate and prepared by ultraviolet-induced polymerization in the presence of crosslinker and composite initiator.