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    Environmentally Sensitive Hydrogels: N-isopropyl acrylamide/Acrylamide/Mono-, Di-, Tricarboxylic Acid Crosslinked Polymers
    (Wiley, 2015) Isikver, Yasemin; Saraydin, Dursun
    Environmentally sensitive hydrogels responsive to various stimuli such as temperature, pH, ionic strength of the medium and the solvent were prepared by using N-isopropyl acrylamide (NIPAM), acrylamide (AAm) and monomers that have various number of carboxylic acid (XA) functionality using N,N-methylene bisacrylamide (Bis) as crosslinker. Hydrogels were prepared via free radical polymerization reaction in aqueous solution. P(NIPAAm-co-AAm) and p(NIPAAm-co-AAm)/XA hydrogels that contain monoprotic crotonic acid (CA) exhibit a lover critical solution temperature (LCST) at 28 degrees C, whereas p(NIPAAm-co-AAm)/IA (IA:itaconic acid), and P(NIPAAm-co-AAm)/ACA (ACA:acotonic acid) hydrogels exhibit a lover critical solution temperature at 30.7 degrees C and 34.4 degrees C, respectively. Spectroscopic and thermal analyses were performed for the structural and thermal characterizations of the prepared hydrogel. The swelling experiments as equilibrium swelling percentages by gravimetrically were carried out in different solvents, at different solutions temperature, pH, and ionic strengths to determine their effects on swelling characteristic of hydrogels. POLYM. ENG. SCI., 55:843-851, 2015. (c) 2014 Society of Plastics Engineers
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    Poly(acrylamide-sepiolite) composite hydrogels: Preparation, swelling and dye adsorption properties
    (Springer, 2006) Ekici, Sema; Isikver, Yasemin; Saraydin, Dursun
    Polymer-clay hydrogel composite was prepared on the basis of polyacrylamide (PAAm) gel containing the clay mineral sepiolite. The properties of swelling and dye adsorption of poly(acrylamide-sepiolite) (AAm/Sep) composite hydrogel were investigated. The parameters of swelling and diffusion in water and dye solutions were calculated for the AAm and AAm/Sep hydrogels. It was found that the equilibrium swelling degree of obtained composite higher than that of AAm gel. Spectroscopic analysis of composite and composite-dye systems was done with FT-IR method. Adsorption of monovalent cationic dyes such as Basic Blue 12 (BB-12) Basic Blue 9 (BB-9), and Basic Violet 1 (BV-1), was studied on the composite. In the adsorption experiments, S (Sigmoidal) type for composite gel adsorption isotherms in the Giles classification system was found. Adsorption studies indicated that the amounts of adsorbed dyes on the AAm/Sep composite hydrogel were increased with following order; BB-12 > BB-9 > BV-1. The composite hydrogel may be considered as good candidate for environmental application to retain more water and dyes.
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    Preparation and Characterization of Nicotine-Selective Hydrogels
    (Wiley, 2016) Isikver, Yasemin; Ecevit, Tugba
    In this study, P(NIPAAm-MAm)/A, which is a new smart polymer on which the temperature sensitivity of N-isopropyl acrylamide monomer and pH sensitivities of methacrylic acid (MA) and itaconic acid (IA) monomers unite, were prepared by free radical polymerization. The influence of crosslinkers on the properties of polymer and adsorption was studied using two different crosslinkers. These new environmentally multistimuli responsive hydrogels were characterized by FTIR, TG, and DSC. In order to determine the swelling behaviors of polymers, the equilibrium swelling studies were carried out at different temperatures and pHs. With the aim of studying the usability of the prepared polymers in the adsorption of nicotine and its pharmaceutical derivatives, the effects of temperature, pH, and adsorbent mass on adsorption equilibrium were studied. (C) 2016 Society of Plastics Engineers
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    Synthesis and characterization of metal ion-imprinted polymers
    (Indian Acad Sciences, 2018) Isikver, Yasemin; Baylav, Sabri
    In this study, ion-imprinted polymeric materials from an aqueous solution were prepared to remove metal ions (M2+) like Ni2+, Co2+, etc. To prepare ion-imprinted polymers (IIPs), acrylic acid derivatives (XA) like acrylamide (AAm), methacrylic acid and itaconic acid were chosen as monomers. Metal ions formed binary chelate complexes with the help of 8-hydroxyquinoline (8-HQ). The solution containing functional monomers and the binary complex were polymerizedwith the help of various cross-linkers [ethylene glycol dimethylacrylate (EGDMA) or trimethylpropane trimethacrylate (TMPTMA)] and the target ion was removed from this polymer through an applicable method to produce IIPs. Furthermore, the control polymers (CPs) were synthesized through the same method without using metal ion. Characterization of the polymeric materials was investigated through spectroscopic (FTIR/ATR), thermal (TGA, DSC) and surface (SEM and XRD) analyses. Functional monomers, cross-linkers and the target ion's species were changed during preparation of IIPs to observe their effect on imprinting of the target ion. Adsorption of the target ion to the prepared IIPs and the factors affecting the adsorption like concentration, pH, temperature, mass, etc. were studied.