Studies onvolve in super absorbent gels based on acrylic acid

ABSTRACT In this study, acrylic based super absorbent polymers were synthesized with inverse suspension polymerization technique to be used for conditioning soil. The said super absorbent polymers were obtained from the aquous solution of monomers dispersed in a continuous organic phase. The inverse suspension polymerization was accomplished with the use of the aquous solution of partly neutralized acrylic acid with a predetermined cross-linker agent/monomer rate in cyclohexan. Sorbitan monostearat was used to obtain the suspension. In order to examine the effect of parameters having influence on the behaviours of super absorbent polymers, optimal conditions were obtained on an empirical basis by adjusting the beginning monomer and cross-linker concentration, the neutralization degree, the initiator type and amount, the surfactant amount and type, the organic phase amount and type, rate of addition of the aquous phase, the temperature, stirring speed, and the type of the mixer. NaOH and KOH, for the neutralization of acrylic acid, 2-hydroxy ethylmetacrylate as a secondary monomer, polyethylene glycol (PEG 200, PEG 1000, PEG 4000) as a pore making agent N,N'-methylendiacrylamide as a cross-linker agent, ethylene glycoldimetacrylate as secondary monomer and a cross-linker agent, potassium persulfate as the initiator, cyclohexane as the organic phase and gas oil, sorbitan monostearat as the surfactant agent were used. The characteristic features of the obtained absorbent polymers such as water absorption capacities and absorption rates were determined experiment were conducted on the soil and plants. İt was observed that the EGDM (ethylene glycoldimetacrylate)-sodium acrylate based polymers had a good absorption capacity (193.4881 g / 1 g), HEMA- sodium acrylate and PEG 4000 - sodium acrylate based polymers has best water absorption rates (43.1744 g / 85 sec and 88.995 g / 105 sec, relatively). The EGDM- sodium acrylate based polymer turned out to yield best results in experiments conducted on plants.