Browsing by Author "Evingür, Gülşen Akın"
Now showing items 1-11 of 11
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Conductivity Percolation of Carbon Nanotubes in Polyacrylamide Gels
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Publisher and Date:(Intech Europe, 2011)
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Drying of Polyacrylamide Composite Gels Formed with Various Kappa- Carrageenan Content
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Publisher and Date:(Springer/Plenum Publishers, 2011)Drying of polyacrylamide (PAAm)-kappa-carrageenan (kappa C) composite gels were monitored by using steady-state fluorescence technique. Disc shaped gels were formed from acrylamide (AAm) and N N'- methylenebisacrylamide(Bis) with various kappa- carrageenan (kappa C) contents by free radical crosslinking copolymerization in water. Pyranine (P) was doped as a fluorescence probe and scattered light I (sc) and fluorescence intensities I were monitored during drying of these gels. It is observed that ...
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EFFECT OF CONTENT AND TEMPERATURE ON THE PHASE TRANSITIONS OF POLYMER COMPOSITES DOPED BY KAPPA CARRAGEENAN AND ALGINATE
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Publisher and Date:(Elsevier Academic Press Inc, 2016)
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Energy needs for drying of PAAm- kappa C composites prepared with various kappa C contents
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Publisher and Date:(European Polymer Federation, 2011)Various polyacrylamide (PAAm) - Kappa Carrageenan (kappa C) composite gels were prepared from acrylamide (AAm) N N'- methylenebisacrylamide (BIS) and different kappa C contents by free radical crosslinking copolymerization in water. Pyranine (P) was introduced as a fluorescence probe and scattered light I-sc and fluorescence intensities I from these gels were monitored during drying at different temperature. The fluorescence intensity of pyranine increased as drying time is increased for all ...
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Fractal dimension and phase transition of graphene oxide (GO) doped polyacrylamide
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Publisher and Date:(ELSEVIER SCI LTD, 2020)Graphene Oxide (GO)- Polyacrylamide composites prepared between 5 and 50 mu l GO were performed by Fluorescence Spectroscopy. The phase transition performed on the composites was measured by calculating the critical exponents, beta and gamma, respectively. In addition, fractal analysis of the composites was calculated by a fluorescence intensity of 427 nm. The geometrical distribution of GO in the composites was calculated based on the power law exponent values using scaling models. While the ...
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In situ steady state fluorescence (SSF) technique to study drying of PAAm hydrogels made of various cross-linker contents
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Publisher and Date:(Elsevier Science, 2009)Drying experiments of polyacrylamide (PAAm) gels were performed using steady-state fluorescence (SSF) spectrometer. Pyranine (P) was introduced as a fluorescence probe and intensity of P from various crosslinker content gel samples was monitored. It was observed that the intensity of P increased during the in situ drying processes. Gravimetrical and volumetric experiments were also performed. An empirical model was derived and introduced to determine the desorption coefficient D of water molecules ...
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Kinetic models for the dynamical behavior of polyacrylamide (PAAm)-kappa-carrageenan (kappa C) composite gels
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Publisher and Date:(Springer, 2015)A fluorescence method was employed for studying the drying and swelling of PAAm-kappa C composite gels which were formed from acrylamide (AAm) and N N'- methylenebisacrylamide (BIS) with various kappa-carrageenan (kappa C) contents by free radical crosslinking copolymerization in water. Composite gels were prepared at 80 A degrees C with pyranine (Py) as a fluorescence probe. Scattered light I (sc) and fluorescence emission intensities I (em) were monitored during drying and swelling of these gels. ...
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Monitoring of dynamical processes in PAAm-MWNTs composites by fluorescence method
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Publisher and Date:(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 radical initiator and a crosslinker respectively. The drying and swelling processes of disc shaped PAAm-MWNT composites were monitored by the steady-state fluorescence technique at various temperatures. Disc shaped composite gels were prepared with pyranine (P) doped as a fluorescence ...
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Steady state fluorescence technique for studying phase transitions in PAAm-PNIPA mixture
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Publisher and Date:(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. NN'-methylenebis (acrylamide) (BIS) and ammonium persulfate (APS) were used as crosslinker and an initiator respectively. Pyranine (8-hydroxypyrene-1 3 6-trisulfonic acid trisodium salt HPTS) was added as a fluoroprobe for monitoring the polymerisation. It was observed that ...
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Swelling Kinetics of PAAm-kappa-Carrageenan Composites: A Fluorescence Technique
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Publisher and Date:(Taylor & Francis Inc, 2011)The steady-state fluorescence (SSF) technique was introduced for studying swelling of disc-shaped polyacrylamide (PAAm) gels containing various amount of kappa-carrageenan (kappa C). They were prepared by free-radical cross-linking copolymerization. N N'-methylenebisacrylamide (BIS) and ammonium persulfate (APS) were added as a crosslinker and an initiator respectively. Composite gels were prepared at 80 degrees C with pyranine as a fluorescence probe. After drying of these gels swelling kinetics ...
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The Role of Pyranine in Characterization of PAAm-kappa C Composites by Using Fluorescence Technique
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Publisher and Date:(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 studying sol-gel transition and swelling of PAAm-kappa C composite gels which were prepared by free-radical crosslinking copolymerization. Pyranine was introduced as a fluorescence probe. Pyranine molecules start to bind to acrylamide polymer chains upon the initiation of the ...
