Saadet Özgümüş

Saadet Özgümüş
İstanbul University-Cerrahpaşa · Department of Chemical Engineering

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50
Publications
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Publications

Publications (50)
Article
The aim of this study is to investigate the effects of the thiolation on the mucoadhesion characteristics of the gelatinized and crosslinked wheat starch-graft-poly(acrylic acid) [(WS-g-PAA)gc] for potential use in drug delivery via vaginal route. Thiolation of (WS-g-PAA)gc was first time realized using l-cysteine hydrochloride monohydrate (CyS) an...
Article
The aim of this study was to prepare and evaluate the mucoadhesive, biocompatible and biodegradable progesterone containing vaginal tablets based on modified starch copolymers for the estrus synchronization of ewes. Starch-graft-poly(acrylic acid) copolymers (S-g-PAA) were synthesized and characterized. The vaginal tablets were fabricated with S-g-...
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Full-text available
Gene delivery is the most innovative therapeutic method in the fi eld of molecular medicine. Viral and nonviral vectors, which are the carrier systems for the gene transfer, are used for the gene delivery. Since the development and use of the fi rst nonviral vector, various synthetic, natural, and modifi ed natural cationic polymers have been used...
Article
Novel exfoliated polyampholyte nanocomposite hydrogels (NH-LDHs) based on acrylic acid (AA), 2-(diethylamino) ethyl methacrylate (2-DEAEMA), N,N-methylenebisacrylamide (NMBA) and layered double hydroxide (Mg–Al–Cl LDH) were synthesized using an in situ free radical addition polymerization method in aqueous media. First, Mg–Al–Cl LDH with a highly c...
Article
The aim of this study was to synthesize and characterize the novel polyampholyte nanocomposite hydrogels (NH) and to investigate the efficiency in the removal of the indigo carmine from the aqueous solutions. Acrylic acid (AA), 2-(diethylamino)ethyl methacrylate (2-DEAEMA) and montmorillonite (MMT) were used as ionic monomers and inorganic componen...
Article
Gene transfer studies, preferred in many biotechnology studies such as in vitro transgenic cell modeling systems, gene therapy, transgenic animal production by cloning, etc., are quite limited due to transfection difficulties on primary cell lines. The main purpose of this study is on the production of biocompatible gene carrier systems with high t...
Article
Continuous hydrolytic depolymerization of polyethylene terephthalate (PET) resin at high temperature and pressure was carried out in a co-rotating twin screw extruder. In this novel process, hydrolysis is achieved by injection of saturated steam at high pressure. Optimum conditions occur at relatively low screw speeds and water/PET ratios. Hydrolys...
Article
The aim of this study is both to design the chitosan (Chi) nanoparticles with different Mw containing the phosphoester bonds and increase their amino function for the transfection. The phosphorylamine-modification of Chi and depolymerized Chi (DChi) was realized using o-phosphorylethanolamine (o-PEA) and characterized, for the first time. The nanop...
Article
In the present study, vinyltrimethoxysilane was used to modify high-ortho novolac resin (NR) to obtain a vinyl silicone-modified phenolic oligomer (Si-mod NR). Subsequently, this oligomer is polymerized with methyl methacrylate. The mid-products (NR and Si-mod NR) and synthesized silicone-modified phenolic/acrylic resin (Ac/Si-mod NR) were characte...
Article
In present study, grafting of poly(methacrylic acid) (PMAA) onto the various types of starches [maize (MS); rice (RS); wheat (WS); potato (PS)] was first time realized by using methacrylic acid (MAA) as monomer and ammonium cerium‐IV‐nitrate (CAN) as initiator system in the aqueous media. The effects of the gelatinization pretreatment and the use o...
Article
Nasal vaccination is considered to be an effective and convenient way of increasing immune responses both systemically and locally. Although various nanovaccine carriers have been introduced as potential immune adjuvants, further improvements are still needed before they can be taken to clinical usage. Chitosan-based nanovaccine carriers are one of...
Article
The aim of this study is to prepare the long linear aliphatic amine pendant group-functionalized chitosan based nanoparticulate gene carrier system with improved properties for the efficient transfection. The amine functionalized chitosan (MChi) was synthesized by using N-(2-hydroxyethyl)ethylenediamine (HE-EDA) and characterized for the first time...
Article
The aim of this study is to develop a novel folic acid conjugated, DL-lysine modified, PEGylated, the 3rd generation hyperbranched polymer (HBP-PEG-Lys-FA) for use in receptor-mediated therapy. 5-fluorouracil, model anti-cancer drug, loaded nanoparticles were found an average size of 177 nm with loading efficiency of 23.18%. In vitro drug release s...
Article
Mucosal vaccination stimulates both mucosal and systemic immunity. However, mucosal applications of vaccine antigens in their free form generally result in poor systemic immune responses and need adjuvantation. In this study, bovine serum albumin loaded, new hybridised poly(β-amino ester)-poly(d,l-lactide-co-glycolide) nanoparticles were prepared b...
Article
Novel mucoadhesive montmorillonite/starch-graft-poly (methacrylic acid) nanocomposite hydrogels (Mt/S-g-PMAA) based on gelatinized wheat starch, an anionic monomer methacrylic acid (MAA), and different amounts of montmorillonite (Mt) as nanoparticles were synthesized according to the conventional grafting reaction mechanism in the aqueous media. Th...
Article
Acrylic monomer based terpolymer/montmorillonite nanocomposite hydrogels (NH-MMTs) synthesized using 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA), 2-acrylamido-2-methlypropane sulfonic acid (AMPS) and 2-hydroxyethyl methacrylate (HEMA) in the aqueous montmorillonite (MMT) suspension were employed as adsorbents for U(VI) removal from aqueous sol...
Article
Waterborne acrylic emulsion was obtained by using methyl methacrylate, ethyl and butyl acrylate monomers. Emulsions containing nanoparticles were prepared by blending the stable dispersions containing SiO2 or MMT nanoparticles. The films were prepared from emulsions and coating tests were applied. The physical properties of prepared emulsions are b...
Article
In this study, the removal of copper(II) and lead(II) ions from aqueous solutions by Starch-graft-acrylic acid/montmorillonite (S-g-AA/MMT) nanocomposite hydrogels was investigated. For this purpose, various factors affecting the removal of heavy metal ions, such as treatment time with the solution, initial pH of the solution, initial metal ion con...
Article
In this study, poly(DMAEMA–AMPS–HEMA) terpolymer/montmorillonite nanocomposite hydrogels were prepared by in situ polymerization technique using 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA), 2-acrylamido-2-methlypropane sulfonic acid (AMPS), 2-hydroxyethyl methacrylate (HEMA) monomers in clay suspension media. N,N-methylenebisacrylamide (NMBA)...
Article
In this study, Acrylic acid (AA)/2-acrylamido-2-methlypropane sulfonic acid (AMPS) hydrogels were prepared by free radical polymerization in aqueous solutions of AA, AMPS, and N,N-methylenebisacrylamide (NMBA) as crosslinker. Potassium persulfate (PPS)/potassium bisulfide (PBS) were used as initiator and accelerator pair. The water absorption capac...
Article
A series of random sulfonated copolyimides containing aliphatic linkages (co-SPIAs) with controlled degrees of sulfonic acid groups were synthesized via a conventional two-step polyimidization method. 2,4-Diaminobenzene sulfonic acid (2,4-DABS) and 1,6-diaminohexane (DAH) were used as sulfonated aromatic diamine and nonsulfonated aliphatic diamine...
Article
The thermal oxidative degradation kinetics of poly(ethylene terephthalate) (PET) copolymers modified with poly(lactic acid) (PLA) were investigated with thermogravimetric analyzer (TGA). The thermal properties of the modified products were also determined by differential scanning calorimeter (DSC) technique. Waste PET (P100) obtained from postconsu...
Article
In this study, we aimed to investigate the removal of basic dyes, including Safranin T (ST), Nile Blue A (NBA), and Brilliant Cresyl Blue (BCB), from aqueous solution with a sulfonated phenol–formaldehyde resin. This sulfonated resin was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The adsorption proper...
Article
A series of sulfonated homo- and random co-polyimides (co-SPI) based on 2,4-diaminobenzenesulfonic acid (2,4-DABS) and 2,5-diaminobenzenesulfonic acid (2,5-DABS) has been synthesized via conventional two-step polyimidization method. 2,4-DABS and 2,5-DABS were used as sulfonated diamine compounds, 4,4′-oxydianiline (ODA) and 4,4′-diaminodiphenyl sul...
Article
The graft copolymerization of acrylic acid (AA) onto starch was carried out with monomer/starch weight ratio = 1.5. Cerium ammonium nitrate (CAN) and N,N′-methylenebis acrylamide (NMBA) were used as initiator and crosslink agent, respectively. Na-montmorillonite was used as nanoparticles. Starch-graft-acrylic acid/Na-MMT (S-g-AA/MMT) nanocomposite...
Article
This paper describes our work on the synthesis of a series of sulfonated homo-/co-polyimides (SPI) which were obtained by post-sulfonation method over three steps. In the first step, 4,4′-oxydianiline (ODA) and 4,4′-diaminodiphenylsulfone (DDS) dissolved in N-methyl pyrrolidone (NMP) were reacted with benzophenonetetracarboxylic dianhydride (BTDA)...
Article
In the present study, we aimed to develop a polyacrylamide gel that could be used instead of bovine cervical mucus in the cervical mucus penetration test (CMPT) to obtain coherent and replicable results in bulls. The frozen semen samples of six Holstein bulls, which were divided into two fertility groups as low and high according to their non-retur...
Article
The nonisothermal crystallization kinetics of poly(ethylene terephthalate) (PET) copolymers modified with poly(lactic acid) (PLA) were investigated with differential scanning calorimetry, and a crystal morphology of the samples was observed with scanning electron microscopy. Waste PET (P100) obtained from postconsumer water bottles was modified wit...
Article
Blends or reaction products of novolac and resol type phenolic resins with waste poly(ethylene terephthalate) (PET) with up to 35% PET waste content, can after compression molding, yield composites with an interpenetrating network of phenolic matrix, supported by thermoplastic PET. Optimal amounts of waste PET improved the mechanical properties of...
Article
A novel type of Si-containing acrylic resins was prepared by two steps and investigated their usage as surface coatings materials. At first a reactive polysiloxane intermediate Z-6018 was reacted with 2-hydroxyethyl methacrylate (HEMA) in toluene at 110°C under N2 atmosphere. After the condensation reaction was stopped, reacted with different acryl...
Article
New silicone modified acrylic resins were synthesized and some of their film properties were investigated. At first, macromer (MC) was synthesized by the condensation reaction of the reactive polysiloxane intermediate (Z-6018) and 2-hydroxyethyl methacrylate (HEMA) in toluene as solvent at 110°C under nitrogen atmosphere. Then, MC was reacted with...
Article
High ortho novolactype phenolic resin and waste poly(ethylene terephthalate) (PET) were used to prepare blends and reaction products. The effect of PET on the thermal oxidative stability of these products was investigated with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and fourier transform infrared spectroscopy (FTI...
Article
Four different types of cross-linked polyimides based on 4,4-diphenylmethane diisocyanate (MDI) were prepared by the reaction of different types of conventional poly(amic acid) intermediates with MDI as a cross-linking agent. Subsequently, they were thermally imidized in order to obtain corresponding cross-linked polyimide structure. The results of...
Article
A series of conventional polyimide (CPI) films, based on pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylicdianhydride (BTDA), were prepared by a two step process, and their dielectrical constant, dielectrical loss, and DC conduction behaviors were studied at different frequencies and voltages. Their dielectrical breakdown voltage, wat...
Article
The purpose of this study is the preparation of hydrolytically degradable copolymers of waste poly(ethylene terephthalate) (PET). To achieve this, we modified PET by using biodegradable poly(lactic acid) (PLA). Modification reactions were carried out in o-nitrophenol as solvent at 140 and 170°C for 8, 16, and 24 h in the presence of dibutil tin oxi...
Article
Postconsumer water bottle poly(ethylene terephthalate) (PET) flakes were depolymerized with ethylene glycol (EG) by the glycolysis reaction in the presence of zinc acetate as the catalyst. In the depolymerization reactions, different weight ratios of PET/EG were used. In order to obtain polyesters used as PVC plasticizers, these glycolysis products...
Article
Modified crosslinked polyacrylamides having different functional groups prepared by transamidation reaction in aqueous and non‐aqueous medium and by Hofmann reaction were used as chelating agents for removal of Cu(II), Cd(II) and Pb(II) ions from aqueous solutions at different pH values. Under non‐competitive conditions, polymers adsorbed different...
Article
Waste poly(ethylene terephthalate) (PET) flakes were depolymerized by using trimethylol propane (TMP) in the presence of zinc acetate as catalyst. Molar ratio of PET/TMP was used as 1/2 and 1/4 in the alcoholysis reactions. In order to obtain PVC plastisols, PVC powder was dispersed into a plasticizer mixture composed of di‐isononyl phthalate (DINP...
Article
A novel cross-linked polyimide (CPI) has been prepared by imidization of cross-linked poly(amic acid) (CPAA). In this work, the Ac conductivity and dielectric properties of this polyimide are presented comparitively with those of conventional polyimide (PI), in the 0.2–100 kHz frequency range and 300–463 K temperature interval. Although the frequen...
Article
A novel type of a Si-containing poly(urethane-imide) (PUI) was prepared by two different methods. In the first method, Si-containing polyurethane (PU) prepolymer having isocyanate end groups was prepared by the reaction of diphenylsilanediol (DSiD) and toluene diisocyanate (TDI). Subsequently the PU prepolymer was reacted with pyromellitic dianhydr...
Article
High performance concrete is a novel construction material, which exhibitis higher workability, greater mechanical properties, and better durability than the concentional concrete. Most important criteria for preparation of high performance concrete are addition of superplasticizers in cement mixtures. Only a small amount of superplasticizers can s...
Article
Simultaneous glycolysis and neutral hydrolysis of waste polyethylene terephthalate (PET) has been carried out at 170 and 190 °C with constant amount of ethylene glycol (EG) and increasing amounts of water, in the presence of xylene. The organic solvent made it possible to employ very low amounts of reactants as well as application of lower temperat...
Article
The effect of composition of graft chains of four types cellulose graft copolymers on the competitive removal of Pb2+, Cu2+, and Cd2+ ions from aqueous solution was investigated. The copolymers used were (1) cellulose-g-polyacrylic acid (cellulose-g-pAA) with grafting percentages of 7, 18, and 30%; (2) cellulose-g-p(AA–NMBA) prepared by grafting of...
Article
Neutral hydrolysis of waste polyethylene terephthalate (PET) has been carried out with different amounts of water and different catalysts, in the presence of xylene. The organic solvent made it possible to employ very little amounts of water, lower temperatures and pressures and providing concentrated ethylene glycol (EG) solutions in contrast with...
Article
New phenolic resins containing titanium and silicon in the main polymer structure were synthesized and some of their properties were investigated. Titanium and silicon contents of the polymers ranged from 2 to 13% titanium and from 2 to 5% silicon. These polymers became insoluble and infusible as the titanium and silicon contents of the products we...
Article
Full-text available
Modified crosslinked polyacrylamides having different functional groups were prepared by Mannich reaction using different amine compounds such as ethylenediamine (EDA), diethylenetriamine (DETA) and triethylenetetramine (TETA) and sulfomethylation reaction. Products were characterized by determination of their basic group content (BGC), hydroxymeth...
Article
Modified polyacrylamide hydrogels were prepared by transamidation and Hofmann reactions using different amine compounds. Products were characterized by their amine value (AV), equilibrium degree of swelling (EDS) and FT-IR spectroscopy. In case of transamidation on crosslinked polyacrylamide (CPAAm) in aqueous media, AV increased with reaction time...
Article
The graft copolymerization of acrylic acid (AA) and 2-acrylamido 2-methylpropane sulfonic acid (AASO3H) onto cellulose, in the presence or absence of crosslinking agent N,N′-methylene bisacrylamide (NMBA), by using different concentrations of ceric ammonium nitrate (CAN) initiator in aqueous nitric acid solution at either 5 or 30°C was investigated...
Article
Continuous hydrolytic depolymerization of polyethylene terephthalate (PET) resin at high temperature and pressure was carried out in a co-rotating twin screw extruder. In this novel process, hydrolysis is achieved by injection of saturated steam at high pressure. Optimum conditions occur at relatively low screw speeds and water/PET ratios. Hydrolys...
Article
To reclaim the monomers or prepare intermediates suitable for other polymers zinc acetate catalayzed glycolysis of waste poly(ethylene terephthalate) (PET) was carried out with ethylene or propylene glycol, with PET/glycol molar ratios of1 : 0.5–1 : 3, in xylene at 170–245°C. During the multiphase reaction, depolymerization products transferred to...

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The main object of this study to increase the efficiency of Somatic Cell Nuclear Transfer (SCNT) on transgenic livestock production.