Abstract: Poly(acrylic acid sodium)/humic acid superabsorbent composite was prepared in aqueous solution by using glow-discharge electrolysis plasma. Acrylic acid and humic acid were used as raw materials and N,N-methylenebisacrylamide as crosslinking agent. The effects of absorbency were examined in detail, such as the discharge voltage, crosslinking agent, neutralization degree of acrylic acid, polymerization temperature, amounts of sodium humate and acrylic acid. The swelling rate in 0.9% sodium chloride solution and the swelling behavior in various pH value solutions were also investigated. The structure and thermal stability of the resulting products were also characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The results show that the discharge voltage, amount of crosslinking agent, sodium humate, acrylic acid, neutralization degree of acrylic acid, reaction temperature were 470 V, 0.6%, 4%, 10%, 60% and 70 ℃, respectively, under the optimal conditions. The superabsorbent has higher water absorbency, i.e. 1152 g/g for distilled water and 89 g/g for 0.9% sodium chloride solution. The retention rate of the composite is about 44.3% after heating to 800 ℃.

Key words: glow discharge electrolysis plasma, humic acids, acrylic acid