Browsing Fakülteler by Author "Pekcan, Önder"
Now showing items 61-80 of 98
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The modifier effects of chymotrypsin and trypsin enzymes on fluorescence lifetime distribution of "N-(1-pyrenyl)maleimide-bovine serum albumin" complex
Özyiğit, İbrahim Ethem; Karakuş, Emine; Pekcan, Önder (Pergamon-Elsevier Science LTD, 2016)Chymotrypsin and trypsin are the well known proteolytic enzymes, both of which are synthesized in the pancreas as their precursors the inactive forms; chymotrypsinogen and trypsinogen and then are released into the duodenum ... -
Monitoring of dynamical processes in PAAm-MWNTs composites by fluorescence method
Evingür, Gülşen Akın; Pekcan, Önder (Taylor & Francis Ltd, 2012)Polyacrylamide (PAAm)-multi walled carbon nanotube (MWNT) composites were prepared by free radical cross-linking copolymerization in water. Ammonium persulfate and NN'-methylenebis (acrylamide) (BIS) were used as a free ... -
Monitoring the gelation of polyacrylamide-sodium alginate composite by fluorescence technique
Evingür, Gülşen Akin; Tezcan, Filiz; Erim, F. Bedia; Pekcan, Önder (Taylor & Francis Ltd, 2012)Polyacrylamide (PAAm)-sodium alginate (SA) composite was prepared with different amounts of SA varying in the range between 0.06% and 2% (w/v). The PAAm-SA composite was characterized by the steady-state fluorescence ... -
Optical energy band gap of PAAm-GO composites
Evingür, Gülşen Akin; Pekcan, Önder (Elsevier Science, 2018)Graphene oxide (GO) can be used as an electron acceptor for polymers. The generation of the exciton in such materials is intimately related to the optical band gap. Polyacrylamide (PAAm) - graphene oxide (GO) composites ... -
Oxygen Diffusion into Multiwalled Carbon Nanotube Doped Polystrene Latex Films Using Fluorescence Technique
Yargı, Önder; Ugur, Saziye; Pekcan, Önder (Springer/Plenum Publishers, 2013)This study examines the oxygen diffusion into polystyrene (PS) latex/multiwalled carbon nanotube (MWNT) nanocomposite films (PS/MWNT) consisting of various amounts of MWNT via steady state fluorescence technique (SSF). ... -
Oxygen Diffusion into Polymer-Clay Composite Films as a Function of Clay Content and Temperature
Uğur, Şaziye; Yargı, Önder; Elaissari, Abdelhamid; Pekcan, Önder (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 ... -
Oxygen diffusion into polystyrene-bentonite films
Uğur, Şaziye; Yargı, Önder; Pekcan, Önder (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 ... -
PAAm-kappa carrageenan composites: drying and swelling with various kappa carrageenan contents
Akın-Evingür, Gülşen; Pekcan, Önder (Polish Acad Sciences Inst Physics, 2012)The purpose of this study is to discuss the role of kappa-carrageenan (kappa-car) in the drying and swelling of polyacrylamide (PAAm)-kappa-car composite. The fluorescence intensity of pyranine increased and decreased as ... -
Particle Size Effect on the Film-Forming Process of PS/PBA Composite Latexes
Uğur, Şaziye; Sunay, M. Selin; Elaissari, Abdelhamid; Pekcan, Önder (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 ... -
Percolation and Film Formation Behaviors of MWNT/PS Nanocomposites
Uğur, Şaziye; Yargı, Önder; Pekcan, Önder (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 ... -
Percolation of glassy regions during photopolymerization of epoxy acrylate in DMF
Doğruyol, Zekeriya; Arsu, Nergis; Doğruyol, Sevnur Keskin; Pekcan, Önder (Elsevier Science SA, 2015)The gelation of epoxy acrylate (EA) 80% and tripropyleneglycol diacrylate (TPGDA) 20% was studied through the use of photo-differential scanning calorimetric (photo-DSC) technique in the presence of a thioxanthone based ... -
Phase Transitions in Pure and Hybrid Hydrogels: A Fluorescence Study
Aktas, Demet Kaya; Evingür, Gülşen Akin; Pekcan, Önder (Wiley, 2009)Recent observations on phase transitions around the critical point showed that the critical exponents differed drastically from percolation results and classical results for pure hydrogel systems depending on monomer ... -
Polymer-Ceramic Nanocomposites
Pekcan, Önder; Uğur, Şaziye (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 ... -
Polymer/carbon nanotube composite film formation: A fluorescence study
Yargı, Önder; Uğur, Saziye; Pekcan, Önder (Wiley-Blackwell, 2014)In this study the effect of multi-walled Carbon nanotube (MWNT) on film formation behavior of Polystrene (PS) latex film was investigated by using steady state fluorescence technique. Films were prepared by mixing of pyrene ... -
Producing critical exponents from gelation for various photoinitiator concentrations; a photo differential scanning calorimetric study
Dogruyol, Zekeriya; Arsu, Nergis; Dogruyol, Sevnur Keskin; Pekcan, Önder (Elsevier Science SA, 2012)Photoinitiated radical polymerization of an 80 wt% epoxy diacrylate (EA) and 20 wt% tripropyleneglycoldiacrylate (TPGDA) mixture with various 2-Mercaptothioxanthone (TX-SH) photoinitiator concentrations was studied by using ... -
The Role of Pyranine in Characterization of PAAm-kappa C Composites by Using Fluorescence Technique
Evingür, Gülşen Akın; Pekcan, Önder (Springer/Plenum Publishers, 2011)Polyacrylamide (PAAm) doped by kappa-carrageenan (kappa C) gels were prepared with various amounts of kappa C varying in the range between 0 wt.% and 3 wt.%. Steady-state fluorescence (SSF) technique was employed for ... -
Slow release of trapped homopolymers from a swelling polymeric gel: A fluorescence study
Erdoğan, Matem; Yağcı, Yusuf; Pekcan, Önder (Taylor & Francis Inc, 2008)In-situ steady-state fluorescence experiments were performed for studying slow release of pyrene-labeled polystyrene chains from polystyrene gels formed by free-radical crosslinking copolymerization. Atom transfer radical ... -
Sorption and Desorption of PVA-Pyrene Chains in and out of Agarose Gel
Kara, Selim; Gacal, Burçin; Tunç, Deniz; Yağcı, Yusuf; Pekcan, Önder (Springer/Plenum Publishers, 2012)In situ steady-state fluorescence (SSF) measurement technique was applied to investigation of pyrene labeled Poly(vinyl alcohol) (PVA-Py) molecules diffusion in and out of agarose gels. Gel samples with four different ... -
Spectroscopic study of film formation from polystyrene latex/TiO2 nanocomposites prepared by dip-coating method
Sunay, M. Selin; Pekcan, Önder; Rahman, Md. Mahbubor; Elaissari, Abdelhamid; Ugur, Saziye (Wiley-Blackwell, 2014)In this study we investigated the influence of TiO2 content and thickness of polystyrene (PS) template on film-formation behavior of PS/TiO2 composites using fluorescence and ultraviolet-visible techniques in conjunction ... -
Steady state fluorescence technique for studying phase transitions in PAAm-PNIPA mixture
Evingür, Gülşen Akın; Aktaş, Demet Kaya; Pekcan, Önder (Taylor & Francis, 2009)The steady state fluorescence (SSF) technique was used to study the sol-gel phase transition during free radical crosslinking copolymerisation of various amounts of acrylamide (AAm) and N-isopropylacrylamide (NIPA) mixtures. ...