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    Öğe
    Radiation crosslinked poly(acrylamide/2-hydroxypropyl methacrylate/maleic acid) and their usability in the uptake of uranium
    (Taylor & Francis Inc, 2002) Saraydin, D; Solpan, D; Isikver, Y; Ekici, S; Güven, O
    The terpolymeric poly(acrylamide/2-hydroxy propylmethacrylate/maleic acid) (AAm/HPMA/MA) hydrogels in the rod form have been prepared by gamma radiation of quaternary mixtures of acrylamide/2-hydroxy propylmethacrylate/ maleic acid/water. Spectroscopic and thermal analyses of AAm/HPMA/MA were made. The hydrogels were used in experiments on swelling, diffusion and adsorptions of uranyl ions from aqueous uranyl acetate solutions. For the hydrogels, the parameters of swelling and diffusion were calculated. In the experiment of uranyl ions adsorption, Type L (Langmuir) adsorption isotherm in Giles classification system was found. Binding parameters such as the initial binding constant (K-i), the equilibrium binding constant (K), monolayer coverage (n), site-size (u), maximum fractional occupancy (theta) were calculated for hydrogel/uranyl ion system by using the linearization methods such as Klotz, Scatchard and Langmuir methods. Thermodynamic parameters such as adsorption free energy (DeltaG), adsorption enthalpy (DeltaH) and adsorption entropy (DeltaS) were also calculated. Finally, the effect of MA contents of the hydrogel and irradiation doses was Studied on the adsorption of uranyl ion from its aqueous solution.
  • [ X ]
    Öğe
    Synthesis, characterization and evaluation of IPN hydrogels for antibiotic release
    (Taylor & Francis Inc, 2004) Ekici, S; Saraydin, D
    We prepared new ternary interpenetrating polymeric networks (IPN) systems containing chitosan, poly(N-vinylpyrrolidone) and poly(acrylamide) polymers. IPNs were synthesized by radical polymerization of acrylamide monomers in presence of glutaraldehyde (G) and N,N'-methylenebisacrylamide as crosslinkers and the other polymers. These IPNs were named as C-P-A. Glutaraldehyde were used in different concentration to control the network porous of IPNs. Spectroscopic and thermal analyses of these cylindrical shaped IPNs were made with fourier transform infrared spectroscopy analysis, thermogravimetric analysis, and thermomechanical analysis. Swelling studies of IPNs were carried out at pH 1.1 and pH 7.4 at 37degreesC. The swelling and diffusion parameters of IPNs in these solutions were calculated. Amoxicillin as a bioactive species was entrapped to the IPNs during synthesis. In vitro release kinetics of IPNs were investigated. The experimental data of swelling and release studies suggest clearly that the swelling and release process obeys second-order kinetics. The release of the entrapped bioactive species from IPNs depends on the degree of crosslinking of the polymer and pH of the medium at body temperature. We observed that amoxicillin release at pH 1.1 was higher than at pH 7.4. As a result, IPNs-based chitosan with different cross-linker concentration could be promising candidates for formulation in oral gastrointestinal delivery systems.