Browsing by Author "Simsek, Murat"

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Functional Copolymer/Organo-MMT Nanoarchitectures. XXII. Fabrication and Characterization of Antifungal and Antibacterial Poly (Vinyl Alcohol-co-Vinyl Acetate/ODA-MMT/AgNPs Nanofibers and Nanocoatings by e-Spinning and c-Spinning Methods
(2015) Rzayev, Zakir M. O.; Erdonmez, Demet; Erkan, Kubra; Simsek, Murat; Bunyatova, Ulviye; 0000-0002-2904-3587
Nanofibrous films and coatings were fabricated by electrospinning and centrifugal spinning of aqueous solutions of poly(vinyl alcohol-co-vinyl acetate)/octadecyl amine-montmorillonite layered silicate nanocomposites with/without in situ generated silver nanoparticles (AgNPs). Characterization of nanofibers were realized by FTIR, XRD, SEM, and thermal analysis methods. It was found that AgNPs significantly accelerated phase separation process providing fine distribution of nanofibers. Antifungal and antimicrobial activities of nanocomposites investigated by using Candida Spp fungals, G-positive and G-negative microorganisms strongly depended on chemical/physical structural factors, and loading silver species. Observed effective properties of nanomaterials can be employed for many applications (e.g., air filtration, food packaging, biomedical).
Multifunctional Colloidal Nanofiber Composites Including Dextran and Folic Acid As Electro-Active Platforms
(2017) Rzayev, Zakir M. O.; Bunyatova, Ulviye; Simsek, Murat; 28385251
This work presents the fabrication and characterization of novel colloidal multifunctional polymer nanofiber composites (NFCs) from water dispersion blends of intercalated silicate layered nanocomposites of poly (2-vinyl-N-pyrrolidone)/octadecyl amine-montmorillonite (ODA-MMT) and dextran/ODA-MMT as matrix and partner polymer intercalated nanocomposites in the presence of NaOH and folic acid (FA) as doping agents by green reactive electrospinning. Chemical and physical structures, surface morphology and electrical properties were investigated. Effects of matrix/partner polymer ratios, doping agents, absorption time of NaOH, and temperature on electrical parameters of NFCs were evaluated. The presence of FA and increasing dextran fraction in NFCs resulted in reducing fiber diameter and improving diameter distribution. High complexing behaviors of matrix/partner polymer chains, organoclay, FA, and NaOH significantly improved conductivity parameters, especially 5-min of absorption time (approximate to 10(-2)-10(-3) Sm-1). The conductivity of the samples decreased with increasing temperature. NFCs fabricated for the first time are promising candidates for various biomedical, electrochemical and electronic applications as electro-active platforms. (C) 2017 Elsevier Ltd. All rights reserved.
Multifunctional electroactive electrospun nanofiber structures from water solution blends of PVA/ODA-MMT and poly(maleic acid-alt-acrylic acid): effects of Ag, organoclay, structural rearrangement and NaOH doping factors
(2016) Simsek, Murat; Rzayev, Zakir M.O.; Bunyatova, Ulviya
Novel multifunctional colloidal polymer nanofiber electrolytes were fabricated by green reactive electrospinning nanotechnology from various water solution/dispersed blends of poly (vinyl alcohol-co-vinyl acetate) (PVA)/octadecyl amine-montmorillonite (ODA-MMT) as matrix polymer nanocomposite and poly(maleic acid-alt-acrylic acid) (poly(MAc-alt-AA) and/or its Ag-carrying complex as partner copolymers. Polymer nanofiber electrolytes were characterized using FTIR, XRD, thermal (DSC, TGA-DTG), SEM, and electrical analysis methods. Effects of partner copolymers, organoclay, in situ generated silver nanoparticles (AgNPs), and annealing procedure on physical and chemical properties of polymer composite nanofibers were investigated. The electrical properties (resistance, conductivity, activation energy) of nanofibers with/without NaOH doping agent were also evaluated. This work presented a structural rearrangement of nanofiber mats by annealing via decarboxylation of anhydride units with the formation of new conjugated double bond sites onto partner copolymer main chains. It was also found that the semiconductor behaviors of nanofiber structures were essentially improved with increasing temperature and fraction of partner copolymers as well as presence of organoclay and AgNPs in nanofiber composite.
Novel Colloidal Nanofiber Electrolytes From PVA-Organoclay/Poly(MA-alt-MVE), and Their NaOH and Ag-Carrying Polymer Complexes
(2016) Simsek, Murat; Rzayev, Zakir M. O.; Acar, Selim; Salamov, Bahtiyar; Bunyatova, Ulviya; 2-s2.0-84956644446; J-5194-2019
Novel multifunctional polymer nanofiber electrolytes with covalence crosslinked structures from various solution blends of reactive intercalated poly(vinyl alcohol)/octadecylamine montmorillonite (as a matrix polymer), poly(maleic anhydride-alt-methyl vinyl ether) (as a partner polymer) and their NaOH-absorbing and Ag-carrying polymer complexes were fabricated via electrospinning. Chemical, physical, morphological, and electrical properties of nanofiber structures were investigated by FTIR, XRD, SEM, and electrical analysis methods. Ag precursors in fiber composites significantly improved phase separation processing, fiber morphologies, diameter distributions, and electrical properties of the fibers. In situ generation of Ag nanoparticles and their distribution on nanofiber surfaces during fiber formation occurred via complex formation between silver cations and electronegative functional groups from both matrix and partner polymers as stabilizing/reducing agents. Electrical resistance and conductivity strongly depended on matrix/partner polymer ratios and absorption time of NaOH solution on nanofibers. Addition of NaOH changed the electrical properties of fiber structures from almost dielectric state to excellent conductivity form. The fabricated unique nanofiber electrolytes are promising candidates for applications in power and fuel cell nanotechnology, electrochemical, and bioengineering processes as reactive semiconductive platforms. (C) 2015 Society of Plastics Engineers
Novel Colloidal Nanofiber Semiconductor Electrolytes from Solution Blends of PVA/ODA-MMT, Poly (Itaconic Anhydride-Alt-2-Vinyl-1,3-Dioxalan) and Its Ag-Carrying Polymer Complex by Reactive Electrospinning
(2016) Rzayev, Zakir M. O.; Simsek, Murat; Bunyatova, Ulviya; Salamovd, Bahtiyar; J-5194-2019
Colloidal polymer nanofibers as non-crystalline solid electrolytes were fabricated by using solution blends of polyvinyl alcohol/octadecyl amine-montmorillonite, alternating copolymer of itaconic anhydride with 2-vinyl-1,3-dioxalane and their Ag-carrying complexes by electrospinning. Chemical-physical structures, morphology, thermal and electrical properties of nanofiber electrolytes were investigated to evaluate their influences on the conductivity and resistance parameters. Successful chemical cross-linking of PVA matrix by reactive partner copolymer was observed via ring-opening esterification/cross-linking. A covalence bridge of partner copolymer between PVA macromolecules not only reinforced the network but also provided extra ion charged sites. Effects of alternating copolymer fraction, organoclay, in situ generated silver nanoparticles, and structural factors on the conductivity of nanofiber thin films were estimated. Conductivity and resistance parameters strongly depended on temperature, conduct time, morphology and in situ structural rearrangements during electrospinning. Addition of reactive organoclay and Agcarrying copolymer significantly improved the conductivity due to enhancing nanofiber structures with carboxylate ion charge sites. (C) 2015 Elsevier B.V. All rights reserved.