Browsing by Author "Uğur, Şaziye"
Now showing items 1-14 of 14
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Conductivity percolation of carbon nanotubes (CNT) in polystyrene (PS) latex film
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Publisher and Date:(Canadian Science Publishing Nrc Research Press, 2010)In this study the effect of multiwalled carbon nanotubes (MWNT) on film formation behaviour and electrical conductivity properties of polystrene (PS) latex film was investigated by using the photon transmission technique and electrical conductivity measurements. Films were prepared by mixing PS latex with different amounts of MWNTs varying in the range between 0 and 20 wt%. After drying MWNT content films were separately annealed above the glass transition temperature (T-g) of PS ranging from 100 ...
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Film Formation of Nano-Sized Hard Latex (PS) in Soft Polymer Matrix (PBA): An Excimer Study
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Publisher and Date:(John Wiley & Sons Inc, 2010)This work reports steady state fluorescence (SSF) technique for studying film formation from pyrene (P)labeled nano-sized polystyrene (PS) and poly(n-butyl acrylate) (PBA) hard/soft latex blends. Blend films were prepared from mixtures of PS and PBA in dispersion. Eight different blend films were prepared in various hard/soft latex compositions at room temperature and annealed at elevated temperatures above glass transition temperature (T(g)) of polystyerene. Monomer (I(P)) and excimer (I(E)) ...
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Film Formation of Poly (methyl methacrylate) Latex With Pyrene Functional Poly (divinylbenzene) Microspheres Prepared by Click Chemistry
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Publisher and Date:(Wiley-Blackwell, 2011)This work reports on the application of steady state fluorescence (SSF) technique for studying film formation from poly(methyl methacrylate) (PMMA) latex and poly(divinylbenzene) (PDVB) microsphere composites. Pyrene (P) functionalized PDVB cross-linked spherical microspheres with diameters of 2.5 mu m were synthesized by using precipitation polymerization technique followed by click coupling reaction. The diameter of the PMMA particles prepared by emulsion polymerization were in the range of ...
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Fluorescence quenching method for monitoring oxygen diffusion into PS/CNT composite films
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Publisher and Date:(Elsevier Science SA, 2013)Oxygen permeabilities of nanocomposite films consisting of multi wall carbon nanotubes (MWNT) and polystyrene (PS) were determined to investigate the oxygen diffusion depending on MWNT and temperature. A method which is based on quenching of an excited phosphorescent by oxygen was applied for the measurements. The composite films were prepared from mixtures of (MWNT) and surfactant-free pyrene (P)-labeled (PS) latexes of various compositions at room temperature. These films were then annealed at ...
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Fluorescence study of effect of particle size in PS latex/Al2O3 nanocomposite films
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Publisher and Date:(MANEY PUBLISHING, 2015)Steady state fluorescence and BioUV-Visible techniques were used to study film formation of polystyrene (PS) latex and Al2O3 composites depending on PS particles size and Al2O3 content. Two film series (SmPS/Al2O3 and LgPS/Al2O3) were prepared covering PS sphere (SmPS: 203 nm
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Fluorescence study of film formation from PS/Al2O3 nanocomposites
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Publisher and Date:(Elsevier Science, 2014)Steady state fluorescence (SSF) and UV-vis (UVV) techniques were used to study the film formation behavior of pyrene (P) labeled polystyrene (PS) latex and Al2O3 (PS/Al2O3) composites depending on PS particles size and Al2O3 content. The close-packed arrays of PS spheres (SmPS: 203 nm ; LgPS: 382 nm) templates on clean glass substrates were covered with various layers of Al2O3 by dip-coating method. Two different film series (SmPS/Al2O3 and LgPS/Al2O3) were prepared in various Al2O3 layer content. ...
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Measurement of oxygen diffusion in PS/PNIPAM films using fluorescence quenching
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Publisher and Date:(Taylor & Francis Ltd, 2015)The diffusion of oxygen into pyrene labelled polystyrene (PS) latex/poly(N-isopropylacrylamide) (PNIPAM) composite films (PS/PNIPAM) was studied based on PS content with the use of fluorescence quenching method. Fluorescence experiments were carried out on composite films containing pyrene as a sensor dye. The Stern-Volmer equation for fluorescence quenching is combined with Fick's law for diffusion to derive mathematical expressions. Diffusion coefficients (D) were produced and found to be decreased ...
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Oxygen Diffusion into Polymer-Clay Composite Films as a Function of Clay Content and Temperature
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Publisher and Date:(Wiley-VCH Verlag GmbH, 2009)A simple fluorescence technique is proposed for the measurement of the diffusion coefficient of oxygen into polystyrene-clay composite films as a function of clay content and temperature. The composite films were prepared from a mixture of surfactant-free pyrene-labeled polystyrene latexes and modified Na-montmorillonite clay of various compositions at room temperature. Diffusion measurements were performed with films at room temperature for seven different clay contents (0 5 10 20 30 50 and 60 ...
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Oxygen diffusion into polystyrene-bentonite films
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Publisher and Date:(Elsevier, 2009)A simple fluorescence technique is proposed for the measurement of the diffusion coefficient of oxygen into polystyrene-clay composite films. The composite films were prepared from the mixture of surfactant-free pyrene (P)-labeled polystyrene latexes (PS) and modified bentonite (MNaLB) at various compositions at room temperature. These films were annealed at 200 degrees C above the glass transition (T-g) temperature of polystyrene for 10 min. Oxygen diffusion into the films was monitored with ...
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Particle Size Effect on the Film-Forming Process of PS/PBA Composite Latexes
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Publisher and Date:(John Wiley & Sons Inc, 2010)In this work the effect of hard particle size and blend ratio on the film formation behavior of hard polystyrene (PS) and soft poly(n-butyl acrylate) (PBA) latex blends was studied by means of steady-state fluorescence and UV-visible techniques in conjunction with atomic force microscopy. Three different sets of latexes were synthesized: PBA latex (diameter 97 nm) pyrene (P)-labeled large PS (LgPS
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Percolation and Film Formation Behaviors of MWNT/PS Nanocomposites
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Publisher and Date:(Elsevier Science Bv, 2011)This study involves the investigation of film formation and electrical conductivity properties of polystrene (PS) latex/multi-walled Carbon nanotube (MWNT) composites. Films prepared from PS/MWNT mixtures with different MWNT content were separately annealed above glass transition temperature of PS. Film formation stages of PS/MWNT composites were followed by monitoring the change in transmitted light intensity I-tr. The surface conductivity of films was found to increase dramatically above 4 wt% ...
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Polymer-Ceramic Nanocomposites
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Publisher and Date:(Spie-Int Soc Optical Engineering, 2009)Steady state fluorescence (SSF) and photon transmission (PT) techniques were used for studying film formation from TiO2 and Al2O3 covered polystyrene (PS) latex particles. These films were annealed at elevated temperatures in 10 min time intervals above glass transition (T-g) temperature of polystyrene. Fluorescence emission I-P and transmitted photon I-tr intensities were measured after each annealing step to monitor the stages of film formation. Films present dramatic increase in both I-tr and ...
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Temperature Dependence of Oxygen Diffusion into Clay-Doped PS Films
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Publisher and Date:(John Wiley & Sons Inc, 2010)Fluorescence technique was employed for the measurement of the diffusion coefficient of oxygen into polystyrene (PS) latex/modified Na-activated bentonite (MNaLB) clay composite films. Three different MNaLB content (0 5 and 20 wt%) composite films were prepared from PS/MNaLB mixtures by annealing them at 200 degrees C above the glass transition temperature of PS for 10 min. To determine the diffusivity of oxygen in PS/MNaLB composite films diffusion measurements were performed over the temperature ...
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Temperature dependence of oxygen diffusion into polymer/carbon nanotube composite films
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Publisher and Date:(Wiley-Blackwell, 2012)This study examines the transport properties of polystyrene (PS)/multiwalled carbon nanotube (MWNT) composite films taking into consideration both MWNT composition and temperature via fluorescence technique. Three different (3 15 and 40 wt%) MWNT content films were prepared from PS/MWNT mixtures by annealing them at 170 degrees C above the glass transition temperature of PS for 10 min. The diffusivity of the PS/MWNT composite was determined by performing oxygen (O2) diffusion measurements within ...
