Olgun Güven

• PhD
• Head of Department at Hacettepe University

Polyelectrolytes are used in different technology systems, such as reducing environmental pollution, producing lithium batteries, achieving better performance, and prolonging half-life. One of the vital applications of polyelectrolytes is in drug delivery systems as a drug carrier to reach the specific desired target organ and increase drug effecti...

In this work, the surfaces of poly (ethylene terephthalate) track-etched membranes (PET TeMs) with pore sizes of 670–1310 nm were hydrophobized with 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate (DFHA) by photoinitiated graft polymerization. Attenuated total reflection FTIR spectroscopy (ATR-FTIR), scanning electron microscopy (SEM) coupled t...

In this work, the surface of poly(ethylene terephthalate) track-etched membranes (PET TeMs) with pore sizes of 670-1310 nm was hydrophobized with 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate (DFHA) by photoinitiated graft polymerization. Attenuated total reflection FTIR spec-troscopy (ATR-FTIR), scanning electron microscopy (SEM) coupled to...

Stimuli-responsive membranes play an important role in the fields of biomedicine, food and chemical industries, and environmental applications, including separation of water–oil emulsions. In this study, we present a method to fabricate pH-sensitive membranes using UV-initiated RAFT graft copolymerization of styrene (ST) and acrylic acid (AA) on po...

Polyallylamine hydrochloride P(AlAm.HCl) is a cationic polymer with many applications because of the existing amines group. Its importance becomes evident as polyvinyl amine polymer cannot be prepared from its monomer via free radical polymerization. Polyvinyl sulfonic acid P(VSA) is an anionic polymer with many applications, such as drug delivery...

This paper describes the desalination process by membrane distillation (MD) using track-etched membranes (TeMs). Hydrophobic track-etched membranes based on poly(ethylene terephthalate) (PET TeMs) with pore diameters from 700 to 1300 nm were prepared by UV-initiated graft polymerization of lauryl methacrylate (LMA) inside the nanochannels. Modified...

PLA/PBAT (Poly (lactic acid)/Poly (butylene adipate-co-terephthalate)) blend is a biodegradable material commonly considered a potential alternative to polymeric products from petroleum sources. PLA is intrinsically brittle, endowed with a low elongation at break and poor impact strength that restricts its use for some applications while PBAT has h...

In this work, we have developed a method for the preparation of pH-responsive track-etched membranes (TeMs) based on poly(ethylene terephthalate) (PET) with pore diameters of 2.0 ± 0.1 μm of cylindrical shape by RAFT block copolymerization of styrene (ST) and 4-vinylpyridine (4-VP) to be used in the separation of water–oil emulsions. The influence...

An easy method is proposed to prepare poly(vinyl pyrrolidone) (PVP) and poly(N-isopropylacrylamide) (PNiPAAm) nanogels with sizes less than 100 nm. The underlying principle is to prepare dilute polymer solutions in acetone/water mixtures where acetone acts to break tridimensional structure of water hence disrupting the H-bonds bridging polymer coil...

In contrast to traditional fillers, clay, in particular, natural smectite clay, represents an environmentally significant alternative to improve the properties of polymers. Compared to conventional nanofillers, smectite clay can effectively enhance the physical and mechanical properties of polymer nanocomposites with a relatively small amount of ad...

In contrast to the traditional fillers, clay, in particular, natural smectite clay represents an environmentally significant alternative to improve the properties of polymers. Compared to con-ventional nanofillers, smectite clay can effectively enhance the physical and mechanical properties of polymer nanocomposites with a relatively small amount o...

Cationic polymers with primary amine groups that can easily be functionalized or coupled with substrates by complexation or hydrogen bonding are especially advantageous in preparing particles for biomedical applications. Poly(vinyl amine) (PVAm) is a cationic polyelectrolyte containing the highest number of primary amine groups among any other poly...

In this article, results of PET track-etched membranes (PET TeMs) hydrophobized by photo-induced graft polymerization of stearyl methacrylate (SM) inside the pores were presented. The effects of monomer concentration, time of irradiation and the nature of the solvent on the degree of grafting and membrane morphology were investigated. The PET TeMs...

The complex formation between allylamine and mineral acids (HCl, H 2 SO 4, H 3 PO 4 ) and their stabilities were investigated by Uv-Vis, DSC and TGA analyses. Free radical polymerization of allylamine salts was achieved by using 2,2′-azobis (2-methylpropanediamine)dihydrochloride at 50 o C under N 2 atmosphere in water. PAlAm synthesized in the pre...

The atmospheric carbon dioxide levels are steadily increasing which requires urgent action for its capture, storage, and utilization. To mitigate CO2 effectively and economically research has been focused to improving CO2 capture and storage technologies. Conventional technologies possess a number of shortcomings including space limitations, high e...

Graphene and its derivatives, such as graphene oxide (GO), have attracted enormous interest from academia and industry because of its unique electrical, mechanical, and thermal properties, which can lead to enhanced material performance. In the present study, low contents of GO were incorporated into the poly (vinyl alcohol-co-ethylene) (EVOH). Fir...

Polyelectrolytes show complexation by the other polymers having opposite charges. Allyamine (AlAm) is a cationic monomer, and vinyl sulfonic acid (VSA) is an anionic monomer. AlAm and its copolymer with VSA are excellent polyelectrolytes that can be used in aqueous systems. In this work, we aimed to synthesize the allylamine hydrochloride-vinyl sul...

Hydrogels with reactive thiourea functional groups were prepared by radiation-induced crosslinking of N-(Hydroxymethyl) acrylamide (HMA) and N-allyl thiourea (ATU) at different ATU content and irradiation doses. P(HMA-co-ATU) hydrogels were then utilized as template for in situ metal nanoparticle (MNP) preparation by the reduction of Ni²⁺, Co²⁺, an...

Polyallylamine hydrochloride P(AlAm.HCl) is a polycationic polymer and Polyvinyl sulfonic acid P (VSA) is an anionic polymer. Therefore, synthesis of copolymer between (AlAm.HCl) and (VSA) in the different mole ratios of feed composition, can be obtained amphiphilic copolymers. To the best of our knowledge, there has not been performed research reg...

Vinyl sulfonic acid (VSA) monomer at various pH values was polymerized by using a special radical initiator 2,2′-azobis(2-methylpropanediamine) dihydrochloride in 50 °C and 50 h by free radical polymerization method. The gravimetric conversions were obtained, and it was found that the conversion was the maximum in acidic media and the minimum in ba...

Vinyl sulfonic acid (VSA) monomer at various pH values was polymerized by using a special radical initiator 2,2'-azobis(2-methylpropanediamine) dihydrochloride in 50°C and 50 hours by free radical polymerization method. The gravimetric conversions were obtained, and it was found that the conversion was the maximum in acidic media and the minimum in...

In this study the synergetic effect of gamma-ray and hydrogen peroxide on the degradation of carbaryl in aqueous solution were investigated. Aqueous solution of carbaryl was exposed to five different irradiation doses in the presence and absence of hydrogen peroxide. The intermediate species and aliphatic acids formed during irradiation were determ...

Azo dyes are employed quite commonly, although they can lead to the formation of carcinogenic aromatic amines. In this study, well-defined molecularly imprinted polymers (MIPs) with good recognition to 3 azo dyes (acid red 26, disperse blue 7 and direct blue 2b) were synthesized via radiation-induced reversible addition-fragmentation chain transfer...

The polymers containing primary amino groups are of great practical importance allowing the preparation of a variety of functionalized derivatives. The most of typical example of poly(vinyl amine) can not be synthesized from corresponding monomer due to its instability. The closest analog, poly(allyl amine) however, despite inherent difficulties wi...

Radiation technology has long been proven as a simple, rapid, green and sustainable technology with macroscale applications in healthcare, industry and environment. Its merits, however, have not been fully utilized in today’s ever growing nanotechnology. Ionizing radiation has beneficial effects for the synthesis and modification of structure and p...

Membrane distillation (MD) is a rapidly developing field of research and finds applications in desalination of water, purification from nonvolatile substances, and concentration of various solutions. This review presents data from recent studies on the MD process, MD configuration, the type of membranes and membrane hydrophobization. Particular imp...

Nanogels/microgels are intramolecularly crosslinked particles with submicron diameters that can swell in a suitable solvent due to their three-dimensional network structure. Nanogels provide beneficial features such as flexibility, biocompatibility, high stability and swelling, fixed shape, large surface/volume ratio, fast stimuli-responsive behavi...

Synthesis of poly(N‐vinylformamide) (PNVF) and its subsequent hydrolysis to convert it to poly(vinyl amine) (PVAm) were performed. Kinetics of acidic and basic hydrolysis of poly(N‐vinylformamide) (PNVF), and products of hydrolysis were investigated by using Fourier transform infrared, size exclusion chromatography, ¹H NMR, and ¹³C NMR spectroscopi...

Nitrogen-doped carbon dots (N-doped C-dots) was synthesized by using poly(vinyl amine) (PVAm) as a nitrogen source and citric acid (CA) as a carbon source via the hydrothermal method. Various weight ratios of CA and PVAm (CA:PVAm) were used to synthesize N-doped C-dots. The N-doped C-dots revealed emission at 440 nm with excitation at 360 nm and we...

Reversible addition-fragmentation chain transfer (RAFT)-mediated and radiation-induced grafting of poly(acrylamide) (PAAm) from polystyrene (PS) cell-culture Petri dishes and subsequent chain extension of the grafts by poly(N-isopropylacrylamide) (PNIPAAm) have been achieved by pre-irradiation of PS by electron beam. Utilizing RAFT polymerization d...

The paper describes desalination by membrane distillation (MD) using ion-track membranes. Poly(ethylene terephthalate) (PET) ion-track membranes were hydrophobized by the immobilization of hydrophobic vinyl-silica nanoparticles (Si NPs). Si NPs were synthesized by the sol-gel method, and the addition of the surfactant led to the formation of NPs wi...

Micro and nano hydrogels developed from natural and synthetic polymers have garnered great deal of attention in scientific and industrial realms due to their higher surface area, degree of swelling and active material loading capacity, softness and flexibility, as well as their similarity to natural tissues. Particularly, biocompatible, non-toxic,...

One of the promising applications of nanomaterials is to use them as catalysts and sorbents to remove toxic pollutants such as nitroaromatic compounds and heavy metal ions for environmental protection. This work reports the synthesis of Cu/CuO-deposited composite track-etched membranes through low-temperature annealing and their application in cata...

The Editor-in-Chief has retracted this article [1] because it shows significant overlap with a previously published article by Pladzyk et al. [2].

A molecularly imprinted membrane for specific removal of 2,4-Dichlorophenoxyacetic acid (2,4-D) was synthesized by γ-initiated polymerization using N-vinyl imidazole as functional monomer and ethylene glycol dimethacrylate (EGDMA) as a crosslinker in methanol:water (1:4 by volume) mixture at room temperature. Functional monomer to template molecule...

The rationale of this work is to investigate the effect of chain length of stabilizing polymer brushes attached to silica surface on the formation and catalytic activity of metallic palladium nanoparticles (Pd NPs). Poly(vinyl pyrrolidone) (PVP) brushes forming a very thin shell were grafted on silica microparticles ([email protected]2) via RAFT me...

Poly(tert‐butyl acrylate) (PtBA) is a versatile hydrophobic macromolecule usually preferred in the development of new materials for a host of applications. PtBA homopolymers with well‐defined structure and controlled molecular weight in a wide range were successfully synthesized via radiation‐induced reversible addition–fragmentation chain transfer...

The generation of metal nanostructures by radiation-induced reduction of copper ions in aqueous dispersions of macromolecular complexes of poly(acrylic acid) and polyvinylimidazolе has been studied in the pH range of 2.3–4.3. It was shown that an effective coordination number of Cu2+ in the complex with polymer units decreased at lower pH, which re...

In this paper, we present the results of liquid low-level radioactive wastes (LLLRW) treatment by direct contact membrane distillation (DCMD) using polyethylene terephthalate (PET) track-etched membranes (TeMs). PET TeMs were modified by styrene and triethoxyvinylsilane (TEVS) using UV-induced grafting. Modification led to increase in the contact a...

Cellulose, the most abundant natural polymer in the world has many desired properties such as biocompatibility, biodegradability, durability, low cost, etc. But it lacks some of the versatile properties of synthetic polymers like compatibility, melt-processability and solubility. To mitigate these drawbacks or to produce new sustainable products, c...

Template molecule selected in this study, namely penicillin G (PG) is a member of β-lactam antibiotics (BLAs) and the first antibiotic found by human and used to treat bacterial diseases. PG imprinted polymers were prepared by grafting onto PE/PP non-woven fabrics via gamma irradiation. Methacrylic acid (MAA) and ethylene glycol dimethylacrylate (E...

Controlling of sizes of nanogels is very important for any biomedical application. In the present study we report a facile and reproducible method of preparing biocompatible nanogels of poly(N-vinyl pyrrolidone) (PVP) which were synthesized by using either electron beam (e-beam) (NGEB) or gamma irradiation (NGG) of dilute aqueous solutions. Nanogel...

In the preparation of polymer-clay nanocomposites the chemical incompatibility between the clay surface and polyolefins can be overcome by using clays organically modified with short chain organic cations. The compatibility can be further enhanced by using functionalized polymer that wets the clay surface while being miscible with the non-polar pol...

Poly(acrylic acid)-poly(ethylene oxide) (PAA-PEO) interpolymer complexes (IPC)s were prepared with equimolar stoichiometric ratio of repeating units and converted to crosslinked nanogels via γ-ray irradiation of aqueous acetone solutions. The effect of acetone concentration on the coil size of nanogels was investigated by dynamic light scattering (...

Many studies report that nanocomposites obtained by dispersion of a small amount nanofiller into the polymer have remarkable improvements achieved in the mechanical and physical properties. However, in order to achieve this great improvement in properties, it is necessary that the nanofillers be dispersed homogeneously into the polymeric matrix. Of...

The effectiveness of membrane-based separations is limited by fouling of the membrane used. In order to mitigate this effect on PET track-etched membranes (PET TeMs), the methods of oxidation in hydrogen peroxide and radiation induced graft polymerization of acrylic acid (AA) and N-vinylimidazole (VIM) were used. The antifouling properties of the m...

Gold nanoparticles (Au NPs) possess unique properties for research due to their high stability and catalytic activity in electron transfer processes, such as hydrogenation reactions. One of the major challenges for application of Au NPs in heterogeneous catalysis is the search for better support materials to further increase their stability and cat...

Polymer/clay nanocomposites were prepared by melt intercalation using torque rheometer. Poly (ethylene-vinyl acetate) (EVA 18) with 18% wt. vinyl acetate was used as polymer, unmodified clay (Na⁺ montmorillonite, MMT), organo-modified clays I44 P, I31 PS and clays modified by in-situ radiation polymerization of charged monomer were used as the nano...

Free radical polymerization technique is the most prevalent form of polymerization from academic and commercial perspectives which is broadly applicable to a wide range of monomers. Versatility of this technique is due to the possibility of using various processes that create the free radicals. Ionizing radiation is one of the most direct and easy...

RAFT polymerization was utilized to imprint atrazine, a model herbicide, onto porous nonwoven fabric via surface-initiated polymerization of methacrylic acid (MAA) using γ-rays for the generation of radicals. Cumyl dithiobenzoate (CDB) and ethylene glycol dimethacrylate (EGDMA) were employed as the RAFT agent and crosslinker, respectively. The surf...

The presence of maleic anhydride moiety in styrene-maleic anhydride (SMA) copolymer makes it a versatile substrate for conjugation of drugs. In this study biocompatible styrene-maleic anhydride (SMA) copolymer with alternating structure was synthesized by gamma irradiation at room temperature in the presence of 2-phenyl-2-propyl benzodithioate (PPB...

Oligomers of 2-methyl nylon3 (2mN3) and 3-methyl nylon3 (3mN3) were synthesized by base-catalyzed hydrogen transfer polymerization (HTP) of methacrylamide and crotonamide, respectively. The detailed structural analyses of 2mN3 and 3mN3 were performed using MALDI-MS, ¹H-NMR, elemental analysis and several end-group analyses to ascertain polymerizati...

Photoinduced graft polymerization of N-vinylimidazole (VI) and graft copolymerization of N-vinylimidazole with acrylic acid (AA) onto track-etched polyethylene terephthalate membranes (PET TeMs) with a pore diameter of 450 ± 15 nm have been systematically studied. The effect of different parameters, such as irradiation time, monomer concentration,...

This study presents the preparation of molecularly imprinted matrices by using radiation-induced grafting technique onto polyethylene/polypropylene (PE/PP) non-woven fabrics. Atrazine imprinted polymers were grafted onto PE/PP non-woven fabrics through the use of methacrylic acid (MAA) and ethylene glycol dimethylacrylate (EGDMA) as the functional...

It is demonstrated, for the first time,that well-known phase transitions induced by changes in temperature in solutions of polymers containing both hydrophilic and hydrophobic functional groups could be followed by noticeable hysteresis effects. A well-known phase transitions accompanied by a sharp change in fluid properties, in particular its opti...

This paper reports on the synthesis and structure elucidation of the track-etched membranes with embedded gold nanotubes (prepared in etched-only and COOH-enriched PET track-etched membranes) as well as comparative testing of the catalytic activity of prepared composites. The carboxylic group functionality was enriched by successive oxidation by hy...

Thermo-sensitivity has been introduced onto poly(ethylene terephthalate) (PET) surfaces by graft copolymerization of N-isopropylacrylamide (NiPAAm). The PET surface was first photo-oxidized in the presence of H2O2, to have enriched concentration of COOH groups which were later reacted with allylamine (AlAm) to introduce vinyl end groups at the surf...

Functional nanogels were prepared from interpolymer complexes (IPC) of poly (vinyl pyrrolidone) and poly (acrylic acid) by gamma irradiation of their aqueous solutions. The coil size of IPCs prepared under different experimental conditions (polymer molecular weight, concentration, mixing ratios, pH and temperature) were measured by Dynamic Light Sc...

Ethylene-vinyl alcohol (EVOH) copolymers are widely used in the food packaging industry as gas barrier properties to oxygen, organic solvents, and food aromas. EVOH is very sensitive to moisture and its gas barrier ability deteriorates in high relative humidity conditions. This work aims to prepare flexible films based on melt-blending high density...

Radiation-induced RAFT polymerization technique was applied to synthesize well-defined molecularly imprinted polymers (MIPs) of erythromycin (ERY). Methacrylic acid (MAA) was grafted onto porous polyethylene (PE)/polypropylene (PP) nonwoven fabrics, under γ-irradiation by employing 2-pheny-2-propyl benzodithioate as the RAFT agent and ethylene glyc...

The kinetic investigation of one-pot synthesis of poly(acrylic acid) (PAA) prepared via gamma radiation induced controlled polymerization was reported. PAA homopolymers were prepared by Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization in the presence of trithiocarbonate-based chain transfer agent (CTA) 2-(Dodecylthiocarbonothi...

Cr(VI) adsorption onto a novel fibrous ethylenediamine-functionalized polyethylene/polypropylene (PE/PP-g-PGMA-EDA) nonwoven fabric was investigated in aqueous solutions. The ethylenediamine functionalities were immobilized on the PE/PP nonwoven fabric through the epoxy groups of poly(glycidyl methacrylate) (PGMA) grafted to the fibers via radiatio...

Very high energies of particulate (accelerated electrons, swift heavy ions) or electromagnetic wave (γ-, X-rays) radiation can be used to initiate free radical based reactions in solids, liquids or gases. Because of non-selectivity of absorption of X-rays, γ rays and accelerated electrons in matter free radicals are generated homogeneously in the b...

The details of the synthesis of amphiphilic block copolymers of poly (tert-butyl acrylate) and poly (N-vinyl pyrrolidone) (PtBA-b-PVP) by radiation-induced RAFT polymerization and preparation of terpolymers by partial conversion of tBA blocks into poly (acrylic acid) was presented. Since N-VP cannot be polymerized by ionic mechanism its block copol...

In this study, swelling and selective mercury adsorption behavior of novel radiation cross-linked acrylamide/crotonic acid (AAm/CA) copolymers have been investigated in aqueous mercury (II) ion solutions. Swelling experiments were performed in water and in the solution of mercury (II) ions at 25°C, gravimetrically. The equilibrium swelling (S) valu...

Natural cellulose-based fibers offer low cost, low density composite reinforcement with good strength and stiffness. Because of their annual renewability and biodegradability, natural fibers have materialized as environmentally-friendly alternatives to synthetic fibers in the last two decades. They are replacing synthetic materials in some traditio...

Polymer electrolyte membranes are key components in electrochemical power sources that are receiving ever-growing demand for the development of more efficient, reliable and environmentally friendly energy systems. Ongoing research is focusing on materials with high ionic conductivity and stability, at low cost. Among different methods, radiation-in...

A novel nonwoven fabric adsorbent having 4-vinylpyridine functional groups was prepared by using radiation-induced emulsion graft polymerization method and grafting 4-vinylpyridine monomer onto a polyethylene-coated polypropylene nonwoven fabric (NWF) in aqueous emulsion solution. The grafting conditions of the 4-vinylpyridine monomer onto the NWF...

An alternative method to improve the compatibility between poly(lactic acid) (PLA) and cassava starch (CS) is proposed and investigated. Admicellar polymerization is used to modify the surface of CS with poly(methyl methacrylate) (PMMA) in order to make it more hydrophobic and hence more compatible with PLA. The increased hydrophobicity of PMMA mod...

Radiation induced grafting method is one of the most promising grafting techniques and it works successfully together with the reversible addition fragmentation chain transfer (RAFT) polymerization, one of the most prominent controlled free-radical polymerization (CRP) methods. This study reports grafting of N,N-dimethylaminoethyl methacrylate (DMA...

In the present work, thermal and mechanical properties of nanocomposites PP+ZrO2 are studied. The presence of zirconium dioxide in PP increases its thermal stability and mechanical properties of nanocomposites. The AFM studies show that a change in upper molecular structure of polypropylene as well as a chipping of structure elements of surface mor...

The main objective of this work is to prepare a renewable cellulosic adsorbent by γ-initiated grafting of poly(glycidyl methacrylate) (PGMA) from cellulose substrate and subsequent modification of PGMA with chelating species, iminodiacetic acid (IDA), for Cd (II), Pb(II) and Cu(II) removal from aqueous media. Modification of PGMA grafted cellulose...

The modification of a poly(ester-urethane) (PUR) surface was carried out using radiation-induced grafting. A thermosensitive layer constructed from N-isopropylacrylamide (NIPAAm) was introduced onto the PUR leading to a change in surface morphology. The functionalization of poly(ester-urethane) (PUR) surface was conducted using radiation-induced gr...

13th Tihany Symposium on Radiation Chemistry

In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate) (PET TeMs) oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation proce...

Poly(1-vinylimidazole) (PVIm) hydrogels were synthesized through free radical polymerization/crosslinking of 1-vinylimidazole (VIm) in aqueous solutions with azobisisobutyronitrile (AIBN) used as the initiator and N,N′-methylenebisacrylamide (MBAAm) as the crosslinking agent. To quaternize PVIm, dimethylsulfate was used as the methylating agent. Pr...

Transurethral resection of bladder tumors close to these areas may stimulate the obturator nerve, causing violent adductor contraction and possible inadvertent bladder perforation. To avoid this reaction, local anesthetic blockade of the obturator nerve as it passes through the obturator canal is effective in stopping adductor spasm during spinal a...

In this work, a multi-scale approach with different analytical methods is applied to study the curing process and the structural properties of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin. This monomer, thermally cured using 4,4'-diaminodiphenilsulfone (DDS) as hardener, is analyzed after 10, 45, 90, and 120 min of reaction time at 180 deg...

The idea of preparing water-soluble chitosan and observing its nanostructural morphology are proposed using irradiation process. The water-soluble chitosan nanoparticles (WSCS-NPs) properties were assessed for a possible use as an antioxidant and reducing agent for a green synthesis of gold nanoparticles (AuNPs). The characteristics of WSCS-NPs wer...