Sürdürülebilir Kalkınma Amaçları
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- MakaleAçık Erişim2026Scopus SJRQ3Investigation of Dielectric Constant and Electrical Conductivity of Poly(MA-co-MMA)/Ce(NO3)3 Composites by Response Surface Methodology for Advanced Dielectric Applications
Torgut, Gulben; Incesu, Rabia
In this study, poly(maleic anhydride-co-methyl methacrylate) [poly(MA-co-MMA)] copolymer and their Ce(NO3)3-filled composites were synthesized and systematically investigated. The copolymer was prepared via free radical polymerization using azobisisobutyronitrile (AIBN) as the initiator in 1,4-dioxane medium. Poly(MA-co-MMA)/Ce(NO3)3 composites were fabricated through a solution mixing technique in accordance with the response surface methodology (RSM) design. Fourier transform infrared spectroscopy (FTIR) results indicated that no significant chemical interaction occurred between the polymer molecule and Ce(NO3)3 particles. Scanning electron microscopy (SEM) images revealed a relatively uniform dispersion of Ce(NO3)3 particles within the polymer, resulting in a rougher surface with increasing filler content and that aggregation occurs at 20 wt%. The presence of Ce(NO3)3 particles in the polymer was confirmed by x-ray diffraction (XRD) analysis. The effects of frequency, applied voltage, and Ce(NO3)3 content on dielectric constant (epsilon) and electrical conductivity (sigma) were optimized using RSM, and the significance of these parameters was evaluated by analysis of variance (ANOVA). An increase in Ce(NO3)3 content significantly enhanced the electrical conductivity, while the applied voltage exhibited no statistically significant effect on dielectric properties. ANOVA results identified Ce(NO3)3 content as the most influential parameter in the developed model.
- MakaleAçık Erişim2026Scopus SJRQ1Evaluation of electrical properties of poly(NIPA-co-St) composites containing neodymium and yttrium
Cetinkaya, Ebru; Karaaslan Ayhan, Nagihan; Torgut, Gulben
In this study, firstly, to obtain neodymium (Nd) and yttrium (Y)-containing composite materials, poly(N-isopropylacrylamide-copolymer-styrene) (poly(NIPA-co-St)) copolymer was synthesized by free radical polymerization method using N-isopropylacrylamide (NIPA) and styrene (St) monomers. Secondly, new composite materials were obtained by adding neodymium and yttrium to this copolymer at different weight ratios (10% and 20%). Structural and morphological characterizations of poly(NIPA-co-St) copolymer, poly(NIPA-co-St)-10%Nd, poly(NIPA-co-St)-20%Nd, poly(NIPA-co-St)-10%Y and poly(NIPA-co-St)-20%Y composite materials were carried out. The electrical properties of the copolymer and composite materials were evaluated by considering the frequency dependence of the dielectric constant (έ), dielectric loss (ε″) and electrical conductivity (σac) properties. At 100 Hz, the έ, ε″, and σac values of the copolymer were 5.12, 0.05, and 2.29 × 10−10 S/cm, respectively. With the addition of 10% Nd, the έ, ε″, and σac values at 100 Hz were calculated as 6.57, 0.10, and 1.79 × 10−9 S/cm, respectively, while with the addition of 20% Nd, these values were calculated as 8.39, 0.15, and 4.78 × 10−8 S/cm at 100 Hz. With the addition of 10% Y, the έ, ε″, and σac values at 100 Hz were calculated as 6.56, 0.053, and 1.81 × 10−9 S/cm, respectively, while with the addition of 20% Y, these values were calculated as 8.57, 0.0058, and 3.70 × 10−8 S/cm at 100 Hz. It can be stated that as the amount of Nd and Y additives to the poly(NIPA-co-St) copolymer increases, the έ, ε″, and σac values increase, indicating an improvement in electrical properties with the addition of Nd and Y elements.
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İncele - MakaleAçık Erişim2024Scopus SJRQ3Structural, Dielectric, and Electrical Properties of Chitosan Composites Doped with Silver for Electrochemical Applications
Ayhan, Nagihan Karaaslan; Torgut, Gulben
In this study, chitosan-silver (Chs-Ag) composites containing Ag in different concentrations (0.01–0.08 M) were prepared. The characterization and structure studies of the composites containing 0.01, 0.02, 0.04, and 0.08 M Ag were carried out, and then the dielectric properties of these composites were examined. The composites were characterized by Fourier transform infrared spectrophotometer (FTIR), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), and thermogravimetric analysis (TGA). The dielectric and electrical properties of these composites were investigated depending on the frequency at room temperature, and these properties were determined using an impedance analyzer. Spectroscopy revealed that the dielectric constant (ε′), dielectric loss (ε′′), and real (Z′) and imaginary (Z″) components of impedance are found to decrease with increased frequency for both Chs and Chs-Ag (0.01M–0.08 M) composites. On the contrary, the AC conductivity (σac) of samples increased with increasing frequency. ε′ and ε′′ values of Chs were lower than when the Ag was added. The AC conductivity was improved by the addition of silver particles. The results show that the dielectric and electrical properties of Chs-Ag samples were improved by using Ag as filler.
AtıfScopus3WoS3OpenAlex4İncele - MakaleYalnız künye2023Scopus SJRQ1Improving dielectric properties, electrical conductivity, and thermal properties of biodegradable polymer composites prepared with lanthanum
Torgut, Gulben; Ayhan, Nagihan Karaaslan; Acikses, Aslisah
The precipitation method was adapted to synthesize the poly(ε-caprolactone-copolymer- ethylene oxide) (ε-CL-co-EO) composite with the salt of lanthanum (La), a rare earth element. This salt was incorporated into the polymer of different weight percentages to study how it affects the thermal and dielectric properties of the polymer. The resulting products were characterized by Fourier Transform Infrared Spectroscopy, X-ray diffractometry (XRD), Scanning electron microscopy (SEM) and thermogravimetric analysis. XRD and SEM data show that the polymer mixes homogeneously with the metal salt. Thermal degradation data show that the thermal stability of composites synthesized with La is lower than that of pure polymer. The dielectric properties and A.C conductivity measurements of the composites were investigated by using impedance analyzer in the frequency range (100 Hz to 20 kHz) at room temperature. The electrical property results of (ε-CL-co-EO)/La composites displayed that dielectric constant (έ), dielectric loss (ε"), tan delta (tan δ) and A.C electrical conductivity (σac) increase with increasing La content. The largest conductivity of (ε-CL-co-EO)/La composite filled with 20 wt% La was 8.80 × 10−8 S/cm, which was 162% times pure (ε-CL-co-EO). In addition, impedance (IZI) of composites was evaluated from the dielectric data. This procedure is eco-friendly and easy to handle, which provides a promising route to polymer composites in the application of the conductivity field.
AtıfScopus6WoS6OpenAlex7İncele - MakaleAçık Erişim2021Nhibitory Property of Poly (AN-co-VP) Copolymer on Some Dermatophyte Fungiand Yeasts Causing Fungal Infections
Torgut, Gulben; Kirbag, Sevda; Sönmez, Pınar Erecevıt; Pıhtılı, Güzin
Antimicrobial susceptibility test for poly (AN-co-VP) copolymer, which we think could be an ideal drug in treatment interventions was evaluated with disk diffusion method and minimum inhibitor concentration. In the antimicrobial measurement data, it was determined that the poly (AN-co-VP) copolymer dissolved in pure water is a significant inhibitory property against the growth of yeast (on Candida spp. with 11.33±0.3 mm barrier area) and dermatophyte fungi (on Epidermophyton sp. and Trichophyton sp.with 12.33±0.3 mm barrier area) (p<0.001) and no inhibitory properties were observed in preventing the growth of all bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus megaterium). MIC limit values that prevent the growth of dermatophytes and yeasts supporting the disc diffusion method are 50-100 μL. This study is an alternative approach in order to limit the spread of superficial fungal infections they cause and eliminate these infections that tend to become chronic since this polymer extract has no inhibitory properties on bacteria but prevents the growth of yeast and dermatophytes.
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İncele - MakaleYalnız künye2021Synthesis, Characterization and Electrical Impedance Analyzer Applications of P(ε-CL-co MMA)/Montmorillonite Composites
Torgut, Gulben; Pıhtılı, Güzin
In this study, Poly(ε-CL-co-MMA) was synthesized and its composites have beenprepared. Methyl methacrylate monomer was polymerized by the ATRP method in the presence of two armed macroinitiator Poly(ε-CL-NCl2). The composites of the copolymer were prepared with bentonite,which is a montmorillonite rate of 3%, 6% and 15% and their dispersion in the polymer was examined. Composites are prepared by dispersing method. The structure of the copolymer was characterized byFT-IR, 1H-NMR, DSC, TGA and SEM anaylsis methods. Different electrical properties of polymer /MMT composites were investigated with impedance analyzer device. Therefore, the effect ofmontmorillonite on the copolymers was examined depend on the frequency and temperature aselectrical. It was observed that electrical properties of polymers prepared with clay were higher thanpure polymer.
- MakaleAçık Erişim2021Grafen Katkılı Nişasta Filmlerinin Dielektrik Özelliklerinin Geniş Frekans Aralığında İncelenmesi
Torgut, Gulben; Gürler, Nedim
Bu çalışmada, gliserol ile plastikleştirilmiş patates nişastası (PN) filmlerine, farklı oranlarda (% 0.5, 1, 2) grafen (G) eklenerek döküm yöntemi ile hazırlanmış filmlerin dielektrik sabiti, dielektrik kayıp ve kayıp tanjantı gibi bazı dielektrik özelliklerinin frekansla değişimleri incelendi. PN’nın saf hali ve G ile hazırlanmış kompozitlerinin (PNG0.5, PNG1 ve PNG2) dielektrik sabiti (έ), dielektrik kayıp faktörü (ε՛՛) ve kayıp tanjantı (tanδ) değerleri oda sıcaklığında frekansın bir fonksiyonu olarak (100 Hz ile 10 kHz arasında) empedans analizör cihazı ile belirlendi. Nişastanın 1 kHz sabit frekans ve oda sıcaklığındaki dielektrik sabiti, dielektrik kayıp ve kayıp tanjantı değerleri sırasıyla 9.20, 4.45 ve 0.48 olarak bulundu. Ayrıca, farklı oranlarda G miktarının (ağırlıkça %0.5, %1 ve %2) filmlerin dielektrik özellikleri üzerindeki etkisi araştırıldı. G konsantrasyonu arttıkça dielektrik sabiti, dielektrik kayıp ve kayıp tanjantı değerlerinde, saf nişastaya göre önemli artış olduğu gözlendi.
AtıfOpenAlex2TR Dizin1İncele - MakaleYalnız künye2020Cevap Yüzey Yöntemi Kullanılarak Poli(VPi–ko-MA) / Grafen Kompozitlerinin İletkenliğinin Optimizasyonu
Torgut, Gulben
Bu çalışmada, öncelikle poli(Vinil pivalat–ko-Maleik anhidrit) [poli(VPi-ko-MA)] kopolimeri serbest radikalikpolimerizasyon yöntemiyle 65 oC’de 24 saat süreyle sentezlenmiştir. FT-IR ile karakterize edilen kopolimerinkütlece farklı miktarlarda Grafen (GF) içeren kompozitleri çözelti döküm tekniği ile hazırlanmıştır. KompozitlerFT-IR ve SEM teknikleri ile karakterize edilmiştir. Uygulanan voltaj, frekans ve GF içeriği arasında kantitatif birilişki elde etmek için cevap yüzey yöntemi (CYY) kullanılmıştır. Ölçülen cevap, kompozitlerin elektriksel (AC)iletkenliğidir. Modeldeki parametrelerin (frekans, voltaj ve GF miktarı) önemi, varyans analizi ile belirlenmiştir(ANOVA). Model, maksimum elektriksel iletkenliği, 1619 Hz frekansta, voltaj 15.56 V'da ve GF miktarı ağırlıkça% 9.99 için 6.93×10-8 S cm-1 olarak öngörmüştür.
AtıfTR Dizin1İncele - MakaleAçık Erişim2020Kopolimerlerin Tuz Stresi Altındaki Mısır Bitkilerine Etkisinin Biyokimyasal Olarak İncelenmesi
Torgut, Gulben; Beker Akbulut, Gülçin
Bu araştırmada, biyobozunur özellik gösteren ve 4 farklı oranda sentezlenen poli(etilen oksit)-ko-(ε- kaprolakton) [poli(EO-ko-ε-CL)] kopolimerinin tarımda tuz stresine karşı cevabını incelemek için mısır (Zea mays L. cv. “72 May 99”) bitkilerine uygulama yapılmıştır. Mısıra, kopolimerler, 200 mM tuz (NaCl) çözeltisi ve hem kopolimerler hem de tuz çözeltisi birlikte uygulanarak kontrol gruplarıyla karşılaştırılmıştır. Kopolimerlerin ve tuzluluğun bitki gelişimine etkisini değerlendirmek için lipid peroksidasyonu, pigment ve toplam karbonhidrat içeriği gibi bazı biyokimyasal analizler yapılmıştır. Kopolimerlerin, klorofil içeriğinin yanı sıra lipid peroksidasyon içeriğinin bir ürünü olan malondialdehit (MDA) ve toplam karbonhidrat içeriği üzerinde de olumlu bir etkisi olduğu saptanmıştır. Ayrıca mısır bitkisinde bu kopolimerlerden poli (EO-ko-ε-CL1:4)’ün, tuzluluğun zararlı etkilerinin önlenmesinde diğer kopolimerlerden daha etkili olduğu gözlenmiştir. Sonuç olarak, incelenen tüm parametrelerin tuz stresinden olumsuz etkilendiği görülürken, kopolimer uygulamasının tuz stresine cevapta olumlu etki oluşturduğu saptanmıştır.
AtıfOpenAlex1İncele - MakaleYalnız künye2020Scopus SJRQ4Biochemical responses of some (Helianthus annuus L.) cultivars to the interaction effects of biodegradable polymer and salt stress
Akbulut, Gulcin Beker; Torgut, Gulben
Salt stress is one of the most important environmental factor limiting plant growth and causing serious agricultural problems in the world. Biodegradable poly(ethylene oxide)-co-(ε-caprolactone) poly(EO-co-ε-CL) copolymer synthesized by ring-opening polymerization (ROP) have been used to reduce this negative effect. For the characterization of this copolymer, the Fourier Transform Infrared (FT-IR), Proton Nuclear Magnetic Resonance (1H-NMR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) techniques were used. To investigate the impact of copolymer and salt (200 mM NaCl) singly and in combination, on two different sunflowers (Helianthus annuus L. cv. 'Düet' and Helianthus annuus L. cv. 'Meteor') a series of experiments were established. In the seedlings grown for 21 days, differences in some metabolic parameters such as chlorophyll-a (Chl-a), chlorophyll-b (Chl-b), carotenoids (Car), total chlorophyll (Chl), total carbohydrate content, and malondialdehyde (MDA) content were examined. According to the result of our study, after the application of NaCl and poly(EO-co-ε-CL), significant changes were observed in the studied biochemical parameters. It was observed that the copolymer in both species had a healing effect against salt stress. Application of 200 mM NaCl caused an increase in MDA of both genotype, particularly in 'Meteor'. Higher Chl-a, Chl-b, total Chl, and Car contents were observed in 'Meteor' as compared to that in 'Düet' under saline conditions. Total carbohydrate content decreased with increasing salt stress in both cultivars.
AtıfScopus1İncele - MakaleAçık Erişim2017Scopus SJRQ2Synthesis, thermal degradation and dielectric properties of poly[2-hydroxy,3-(1-naphthyloxy)propyl methacrylate]
Biryan, Fatih; Demirelli, Kadir; Torgut, Gulben; Pihtili, Guzin
2-Hydroxy-3-(1-naphthyloxy)propyl methacrylate (NOPMA) monomer was synthesized from reaction of 2-[(2-naphthyloxy)methyl]oxirane with methacrylic acid in the presence of pyridine. The polymerization of NOPMA was carried out by free radical polymerization method in the presence of AIBN at 60 A degrees C. The structure of monomer and polymer was characterized by H-1-NMR, C-13-NMR and FT-IR spectroscopy techniques. The glass transition temperature and average-molecular weights of poly(NOPMA) were measured using differential scanning calorimetry and gel permeation chromatography, respectively. The thermal degradation behavior of poly(NOPMA) has been investigated by FT-IR studies of the partially degraded polymer and thermogravimetry. The cold ring fractions (CRFs) were collected at two different temperatures, initially fraction-1 (CRF1) is from room temperature to 320 A degrees C, and the other fraction-2 (CRF2) is from 320 to 500 A degrees C. The volatile products of the degradation were trapped at -195 A degrees C (in liquid nitrogen). All the fractions were characterized by FT-IR, H-1 and C-13-NMR spectroscopic techniques, and the cold ring fractions (CRFs) were also characterized by GC-MS. For the degradation of polymer, the major compound between products of CRFs is alpha-naphthol. The GC-MS, FT-IR and NMR data showed that depolymerization corresponding to monomer was not prominent below 320 A degrees C in the thermal degradation of poly(NOPMA). The mode of thermal degradation containing formation of the major products was identified. The dielectric permittivity (epsilon'), the loss factor (epsilon aEuro(3)) and conductivity (sigma(ac)) were measured using a dielectric analyzer in the frequency range of 50 Hz to 20 kHz.
AtıfWoS17OpenAlex22İncele - MakaleAçık Erişim2017Scopus SJRQ1Application of response surface methodology for optimization of Remazol Brilliant Blue R removal onto a novel polymeric adsorbent
Torgut, Gulben; Tanyol, Mehtap; Biryan, Fatih; Pihtili, Guzin; Demirelli, Kadir
The poly[2-hydroxy-3-(1-naphthyloxy)propyl] methacrylate [poly(NOPMA)] was used as a novel adsorbent for the removal of Remazol Brilliant Blue R (RBBR) known as a reactive dye. Physico-chemical properties of polymer were analyzed by FT-IR and SEM before and after dye adsorption. The Langmuir and Freundlich isotherms were used to explain the adsorption equilibrium, and when it was compared with each other it was seen that the adsorption process was well explained by the Langmuir isotherm model and showing a monolayer adsorption capacity for RBBR of 238.10 mg/g. Kinetic models known as pseudo-first-order, pseudo-second-order and intra-particle diffusion model were utilized to analyze the mechanism of adsorption, and results indicated that was an adsorption kinetic suitable with the pseudo-second-order. The thermodynamic parameters (∆Ho, ∆So, ∆Go) indicated that the adsorption process was spontaneous and endothermic. To optimize the study conditions, the effects of the concentration of RBBR, adsorbent amount and contact time on the adsorption were investigated by response surface methodology (RSM). According to RSM results, maximum RBBR removal was reached at the optimum initial dye concentration of 60.85 mg/L, adsorbent dosage of 0.04 g/50 mL and contact time of 59.91 min.
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