Hydrogels obtained from acrylamide, maleic acid, acrylic acid and octylmonoitaconate: synthesis, absorbent capacity and pH variations in copper sulfate solutions

Abstract

Acrylamide (AAm)/maleic acid (AM), acrylic acid (AAc)/maleic acid (AM) and acrylic acid (AAc)/2 -methylenebutanedioic acid octylesther (MI-8) hydrogels were sinthetysed in presence of amonium persulfate as initiator and N,N”™-methylenebisacrylamide as crosslinking agent. The grade of hydrogels swelling was determined by two test at diferent temperatures: 25 and 37°C. The hydrogels swelling also was studied in divalents cations salts solutions, like copper by way of plasma spectroscopy emition. The swelling of synthesised hydrogels test shows isothermal that extends asinthotically to the equilibrium. It was demonstrated that the maleic acid content had a direct influence in the swelling properties (an increment of 30% in AM rise the content of water in the hydrogel in 12%). Respect to the copper cations adsorption, we found that the concentration decrease in the initial solution after to be in contact with the hydrogels. More over, pH variation was measured allowing under stand the reaction mechanism between the hydrogels and metallic ions.