Browsing Mühendislik ve Doğa Bilimleri Fakültesi by Author "Evingür, Gülşen Akin"
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Cation Effect on Slow Release from Alginate Beads: A Fluorescence Study
Kaygusuz, Hakan; Erim, F. Bedia; Pekcan, Önder; Evingür, Gülşen Akin (Springer/Plenum Publishers, 2014)In this study spherical alginate beads containing pyranine (P-y) as a fluorescence probe were prepared by ionotropic gelation of a sodium alginate solution. The steady state fluorescence technique was used to study pyranine ... -
Critical Exponents of Gelation and Conductivity in Polyacrylamide Gels Doped by Multiwalled Carbon Nanotubes
Aktas, Demet Kaya; Evingür, Gülşen Akin; Pekcan, Önder (Taylor & Francis Ltd, 2010)Polyacrylamide (PAM) doped by multiwalled carbon nanotube (MWNT) gels were prepared with different amounts of MWNTs varying in the range between 0.1 and 15 wt%. The PAM-MWNT composite gels were characterized by the steady ... -
Drying of polyacrylamide-multiwalled carbon nanotube (MWNT) composites with various MWNTs contents: a fluorescence study
Evingür, Gülşen Akin; Pekcan, Önder (Walter De Gruyter Gmbh, 2013)We studied the drying of polyacrylamide (PAAm)-multiwalled carbon nanotube (MWNT) composites prepared by free radical crosslinking copolymerization in water with a steady state fluorescence technique. Composite gels were ... -
Effect of Calcium Ion Concentration on Small Molecule Desorption from Alginate Beads
Evingür, Gülşen Akin; Kaygusuz, Hakan; Erim, F. Bedia; Pekcan, Önder (Taylor & Francis Inc, 2014)Spherical alginate beads were prepared by ionotropic gelation of sodium alginate through the use of calcium ions. Pyranine (Py) was added to the alginate solution as a small molecule probe for fluorescence studies. Desorption ... -
Effect of LCST on the swelling of PAAm-NIPA copolymers: a fluorescence study
Evingür, Gülşen Akin; Pekcan, Önder (Springer, 2012)Temperature sensitive copolymers were prepared by free radical crosslinking copolymerization in aqueous solution with different molar percentage of N-isopropylacrylamide (NIPA) and acrylamide (AAm) monomers. NN'-methylenebis ... -
Effect of multiwalled carbon nanotube (MWNT) on the behavior of swelling of polyacrylamide-MWNT composites
Evingür, Gülşen Akin; Pekcan, Önder (Sage Publications Ltd, 2014)The purpose of this paper is to discuss the role of multiwalled carbon nanotube in the swelling of polyacrylamide-multiwalled carbon nanotube composites. Swelling experiments were performed in water at various temperatures ... -
Elastic percolation of swollen polyacrylamide (PAAm)-multiwall carbon nanotubes composite
Evingür, Gülşen Akin; Pekcan, Önder (Taylor & Francis Ltd, 2012)Polyacrylamide (PAAm)-multiwalled carbon nanotube (MWNT) composites were prepared via free radical cross-linking copolymerization with different amounts of MWNTs varying in the range between 0.1 and 50 wt%. The mechanical ... -
Elastic Properties of a Swollen PAAm-NIPA Copolymer with Various NIPA Contents
Evingür, Gülşen Akin; Pekcan, Önder (Taylor & Francis, 2014)Copolymer based on cross-linked polyacrylamide (PAAm) having N-isopropylacrylamide (NIPA) was prepared and their elastic properties were studied as a function of NIPA contents. NIPA content dependency of the shear modulus ... -
Elasticity Study of PAAm-kappa C Composite Prepared in Various kappa C Content and Measured at Several Temperatures
Evingür, Gülşen Akin; Pekcan, Önder (Polish Acad Sciences Inst Physics, 2015)Polyacrylamide (PAAm)-kappa carrageenan (kappa C) composite gels were prepared via free radical crosslinking copolymerization with various (w/v) percentages of kappa C in the range between 0.5 and 3 (w/v)% of kappa C . ... -
A Fluorescence Study on Swelling of Hydrogels (PAAm) at Various Cross-Linker Contents
Aktas, Demet Kaya; Evingür, Gülşen Akin; Pekcan, Önder (Wiley, 2009)Disk-shaped acrylamide (AAm) gels were prepared from AAm with various NN'-methylenebisacrylamide (Bis) contents as cross-linker in the presence of ammonium persulfate as an initiator by free-radical cross-linking ... -
Fluorescence technique for monitoring swelling of PAAm-kappa-carrageenan gel composites
Evingür, Gülşen Akin; Aktaş, Demet Kaya; Pekcan, Önder (Shaker Publishing, 2009)Steady-state fluorescence (SSF) technique was employed for studying swelling of polyacrylamide (PAAm) gels with various content of kappa- carrageenan. Disc shaped composite gels were prepared by free-radical cross/inking ... -
Gelation electrical conductivity and elasticity of PAM- MWNT
Evingür, Gülşen Akin; Pekcan, Önder (Cambridge Univ Press, 2011)Polyacrylamide- Multiwalled carbonnanotube (PAM- MWNT) composites were prepared via free radical crosslinking copolymerization with different amounts of MWNT varying in the range between 0.1 and 15 wt. %. PAM- MWNT composite ... -
Gelation of PAAm-PVP composites: A fluorescence study
Evingür, Gülşen Akin; Kaygusuz, Hakan; Erim, F. Bedia; Pekcan, Önder (World Scientific, 2014)Hybrid hydrogels are a new class of composite materials. Polyacrylamide (PAAm) hydrogels are mainly produced by free radical crosslinking copolymerization (FCC) of AAm in the presence of N N'-methylene bis (acrylamide) ... -
Investigation of Drying of Poly(N-isoproplacrylamide-co-acrylamide) by Fluorescence Technique
Evingür, Gülşen Akin; Pekcan, Önder (Wiley-Blackwell, 2013)The steady-state fluorescence technique was performed on drying of various molar percentages of poly(N-isopropylacrylamide-co- acrylamide) [poly(NIPA-co-AAc)] to elucidate the mechanism of temperature-induced phase separation ... -
Mechanical properties of graphene oxide-polyacrylamide composites before and after swelling in water
Evingür, Gülşen Akin; Pekcan, Önder (Springer, 2018)Polyacrylamide (PAAm) hydrogels have been proposed for use as promising biomaterials in biomedical and tissue engineering but their poor mechanical and water-retention properties have hindered their development. Graphene ... -
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 ... -
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 ... -
Studies on Drying and Swelling of PAAm-NIPA Composites in Various Compositions
Evingür, Gülşen Akin; Pekcan, Önder (Wiley-Blackwell, 2011)The steady-state fluorescence technique was introduced for studying the drying and swelling of disc-shaped PAAm-NIPA composites. Disc-shaped gels were formed with various acrylamides (AAm) and N-isopropylacrylamides (NIPA) ... -
Superelastic percolation network of polyacrylamide (PAAm)-kappa carrageenan (kappa C) composite
Evingür, Gülşen Akin; Pekcan, Önder (Springer, 2013)The elasticity of the polyacrylamide (PAAm)-kappa carrageenan (kappa C) composite was determined as a function of (w/v-%) kappa C content at 40 A degrees C. The gel composites studied contained various percentages (w/v-%) ...