Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2025Scopus SJRQ2Response surface method (RSM) for optimization of electrical properties of polymer/CdS composites for dielectric capacitors
Torğut, Gülben; İncesu, Rabia
This paper aims to present the statistical evaluation of dielectric constant (έ) and conductivity (σ) performance of composites preparing Maleic Anhydride (MA) and Styrene (St) polymer with various amounts of Cadmium Sülfide (CdS) by analysis of variance (ANOVA) model. For this purpose, frequency, applied voltage and CdS amount at different weight percentages were selected as input factors while dielectric constant and conductivity of the composites were selected as the response. Analysis of input factors was performed, RSM method was designed and used for estimation of response factor. From the analysis results, we found that high values of dielectric constant and conductivity were strongly related to frequency and CdS amount. However, we found that applied voltage in the selected ranges did not have a significant effect on both factors. The structural properties of the composites were investigated by Fourier Transform Infrared Spectroscopy (FTIR). The surface morphology was investigated by Scanning Electron Microscopy (SEM). The presence of CdS in polymers has been proven by X-Ray Diffraction (XRD). The thermal properties of polymers were examined by thermogravimetric analysis (TGA).
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İncele - MakaleAçık Erişim2024Scopus SJRQ2Enhanced impedance, electrical conductivity, dielectric properties for colloidal starch-g-poly (methyl methacrylate) supported with semiconductor cadmium sulfide
Torğut, Gülben; Gürler, Nedim
In this study, starch-graft-poly (methyl methacrylate) (starch-g-PMMA) composites doped with different amounts (5, 10, and 15 wt%) of cadmium sulfide (CdS) particles were fabricated for electrical measurements using in-situ polymerization technique. The structural characterization of the samples was studied. The dielectric and conductivity properties of the composites were investigated using impedance analyzer depending on the frequency (100 Hz–20 kHz) at room temperature. Spectroscopy revealed that the dielectric constant (ε′), dielectric loss (ε′′), and real (Z) components of impedance are found to decrease with increasing frequency for both starch-g-PMMA and starch-g-PMMA (5, 10, and 15 wt%) composites. On the contrary, the AC conductivity (σac) of samples increased with increasing frequency. In addition, ε′ and ε′′ values of starch-g-PMMA were lower than composites that added CdS. When the CdS content increased from 0 to 15%, ε′ increased from 5.62 to 15.10 at 100 Hz. AC conductivity was improved after adding the CdS particles. The maximum conductivity value for starch-g-PMMA15%CdS is found to be 3.07 × 10–7 at 100 Hz. When the dielectric properties of composites are evaluated, it is concluded that it is an exciting material for electronic applications in technology.
AtıfScopus9WoS8OpenAlex10İncele - MakaleYalnız künye2023Scopus SJRQ2Antibacterial activity of novel synthesized chitosan-graft-poly(N-tertiary butylacrylamide)/neodymium composites for biomedical application
Yazdıç, Ferit Can; Karaman, Altuğ; Torğut, Gülben; Ayhan, Nagihan Karaaslan
In this present study, composites of chitosan-graft-poly(N-tertiary butylacrylamide) (CH-graft-poly(N‑tert‑BAAm)) copolymer, with Neodymium (Nd), an important rare earth element, were prepared by precipitation technique. Nd was successfully incorporated into the polymer of different weight percentages (0.5%, 1%, and 2%) without any degradation. The effect of neodymium additives on the structural, morphological, and antibacterial activities against gram-positive bacteria and gram-negative bacteria of the polymer was analyzed using various instrument techniques. X-ray diffraction (XRD) results together with Fourier Transform Infrared (FT-IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) studies confirmed the morphology of Nd-doped CH-graft-poly(N‑tert‑BAAm) composites without any other impurities. The antibacterial effect of Nd was studied by adding it to the copolymer in a weight ratio of 0.5%–2%. The antibacterial effect of neodymium concentration on four different strains of bacteria was investigated: Escherichia coli (ATCC 25922) (E. coli), Pseudomonas aeruginosa (DSM 50071) (P. aeruginosa), Bacillus subtilis (DSM 1971) (B. subtilis), and Staphylococcus aureus subsp. aureus (ATCC 25923) (S. aureus). The antibacterial activities of the obtained composites were determined using the Agar Well Diffusion Assay Method. Experimental results show that Nd binds well to CH-graft-poly(N‑tert‑BAAm). Activity against E. coli, P. aeruginosa, B. subtilis, and S. aureus subsp. aureus creates a potential for pharmaceutical and biomedical applications.
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İncele - MakaleAçık Erişim2023Scopus SJRQ2Binary PCL–waste photopolymer blends for biodegradable food packaging applications
Gürler, Nedim; Pekdemir, Mustafa Ersin; Torğut, Gülben; Kök, Mediha
The aim of this study is to prepare waste photopolymer (WPP) / poly ɛ-caprolactone (PCL) blends that can be used in food packaging with different ratios (5%, 10%, 20% and 30%) WPP. The structural properties of the blend films were characterized by attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Opacity, surface color, water vapor permeability and shape memory properties of these films were examined. Pure PCL film exhibited more thermal stability compared to PCL/WPP blend films. Therewithal, the glass transition temperature of the pure PCL film showed a shift. Water vapor permeability improved with the addition of WPP. L*, a* and transmittance values reduced with increasing WPP, but b* value increased. It was thought that these polymer blends would enable to be used as packaging material in terms of compatibility and waste evaluation.
AtıfScopus14WoS13OpenAlex14İncele - MakaleYalnız künye2022Scopus SJRQ2Physicomechanical, thermal and dielectric properties of eco-friendly starch-microcrystalline cellulose-clay nanocomposite films for food packaging and electrical applications
Gürler, Nedim; Torğut, Gülben
Potato starch (PS) films reinforced with microcrystalline cellulose (MCC) were prepared with casting solution, and the effect of montmorillonite (MMT) clay in different proportions (1, 3, 5 and 10 wt%) using nanofiller was established. The films were investigated by Fourier transform ınfrared (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), tensile strength, opacity, colour, water vapour permeability and solubility. Tensile strength for nanocomposite films depending on the clay content was increased significantly from 0.64 to 1.89 MPa. The water vapour permeability of nanocomposite films was improved compared to the PSMCC blend without MMT. Also, dielectric properties and electrical conductivity of films were studied. The dielectric permittivity (έ), the dielectric loss (ε˝) and the electrical conductivity (σ) increased with increasing MMT content at frequencies between 100 Hz to 10 kHz. This nanocomposite with improved functional properties could be used in potential food packaging materials and electrical applications.
AtıfScopus21WoS19İncele - MakaleAçık Erişim2022Scopus SJRQ2Optimization of Electrical Conductivity of SA-graphene Nanocomposites Using Response Surface Methodology
Şahal, Hakan; Torğut, Gülben; Canpolat, Erdal
Synthesis and characterization of 4-{(E)-[(5-bromo-2-hydroxyphenyl)methylidene]amino}-N-carbamimidoylbenzene-1-sulfonamide(SA) and its composites with graphene(SA-GF) were performed. Compound SA and SA-GF were characterized by FTIR and 1H NMR. The GF dispersion in the composites was analyzed by means of scanning electron microscopy(SEM) for morphology. Thermal properties of SA and nanocomposites were investigated using differential thermal analysis(DTA) and thermogravimetric analysis(TGA). The optimum electrical conductivity of the new sulfonamide-based Schiff base was determined to be 1.78×10−5 S/cm at a frequency of 9923 Hz, an applied voltage of −19 V, a mass fraction of 9.38% for graphene loading using a central composite design in the response surface methodology. The significance of the selected parameters(frequency, voltage and GF amount) in the model was determined by the analysis of variance(ANOVA). The results showed that frequency and graphene loading represent important model terms and have considerable effects on the conductivity of SA.
AtıfScopus3WoS3OpenAlex2İncele - MakaleAçık Erişim2022Scopus SJRQ2Synthesis, characterization, and evaluation of antimicrobial performance of N-[3-(dimethylamino)propyl]methacrylamide based copolymer on pathogens
Pıhtılı, Güzin; Erecevit Sönmez, Pınar; Biryan, Fatih; Torğut, Gülben
In this study, poly{N-[3-(dimethylamino) propylmethacrylamide-co-acrylonitrile}; [P(DMAPMA-co-AcN)] copolymer was polymerized by free radical polymerization (FRP) in the presence of azobisisobutyronitrile (AIBN) initiator at 60°C. The structure of the synthesized polymer was characterized by the Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) methods. The bactericidal and fungicidal effects of the solutions prepared by adding methanol to this copolymer to prevent the growth of pathogenic bacteria, yeast, and fungi were evaluated by disk diffusion and broth microdilution method. Since the resistance of bacteria, yeast and fungi, which adversely affect human health, to antibiotics is an important issue, and there has not been any study on the antimicrobial properties of this copolymer, it has directed us to investigate its antimicrobial properties. According to antimicrobial susceptibility tests: The polymer solution showed a broad spectrum of antimicrobial action with 12.3–14.3 mm/inhibition zone diameter on Pseudomonas aeruginosa, Klepsiella pneumoniae, Enterococcus faecalis bacteria, Candida tropicalis, Epidermophyton floccosum yeast and fungi and showed a narrow spectrum of effect on inhibition of the growth of Candida albicans with 10.3 mm/inhibition zone diameter. No antimicrobial effects were observed on Staphylococcus aureus. The minimum inhibition concentration (MIC) value on the test microorganisms was determined as 125–31.25 μl. The data obtained prove that the polymer is in the same group as the interaction of bactericidal and fungicidal drugs. It is also important as a polymer with antimicrobial properties. This study aimed to produce a new polymer with antimicrobial properties. This polymer can be a new and yielding antimicrobial representative in different areas.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2022Scopus SJRQ1Chitosan-graft-poly(N‑tert‑butylacrylamide) Copolymer: Synthesis, Characterization and Optimization of Tetracycline Removal Using RSM
Tanyol, Mehtap; Torğut, Gülben
In the present study, a graft copolymer was synthesized in accordance with the free radical method using N-tertiary butylacrylamide monomer on chitosan, which is an environmentally friendly polymer. The chemical structure and surface morphology of the newly synthesized graft copolymer were determined by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. Moreover, the thermal behavior was analyzed by thermogravimetric analysis. The chitosan-graft-poly(N‑tert‑butylacrylamide) graft copolymer was used as an adsorbent for the rapid removal of tetracycline from aqueous solutions in order to investigate its applicability. Response surface methodology (RSM) was employed for the optimization of the study conditions, namely adsorbent dosage (0.01–0.04 g 100 mL−1), reaction time (10–90 min) and initial tetracycline concentration (10–100 mg 100 mL−1). The effects of these conditions on tetracycline uptake capacity were examined and the results were statistically analyzed. The RSM results showed that the maximum tetracycline uptake capacity of 104.81 mg g−1 was achieved under the following conditions: adsorbent dose of 0.03 mg 100 mL−1, reaction time of 51.12 min and initial tetracycline concentration of 97.99 mg L−1. ANOVA based on central composite design combined with RSM showed a good agreement between the experimental values and quadratic model estimates, thus resulting in a coefficient (R2) of 0.9118 for tetracycline uptake. The kinetics, isotherms, and thermodynamics of adsorption were examined, and results showed that equilibrium data fitted the Freundlich isotherm model, and the adsorption kinetics of tetracycline followed pseudo-second-order model. Thermodynamic parameters like the enthalpy − 10.39 kJ mol−1 (ΔH°), entropy 0.044 kJ mol−1 K−1 (ΔS°) and Gibbs free energy − 23.26 kJ mol−1 (ΔG°) were evaluated and also, ΔG° shows a negative values indicating that the adsorption process was exothermic and spontaneous. The findings demonstrated that the chitosan-graft-poly(N‑tert‑butylacrylamide) copolymer is an effective adsorbent for pharmaceutical wastewater treatment.
AtıfScopus11WoS12OpenAlex11İncele - MakaleYalnız künye2022Scopus SJRQ2Synthesis, characterization, pH-sensitive swelling and antimicrobial activities of chitosan–graft-poly(hydroxyethyl methacrylate) hydrogel composites for biomedical applications
Torğut, Gülben; Yazdıç, Ferit Can; Gürler, Nedim
In this paper, 2-hydroxyethyl methacrylate (HEMA) was graft copolymerized onto chitosan (CHI) at different ratios using a radical initiator. The grafted hydrogel composites were then characterized by attenuated total reflection Fourier transform ınfrared spectroscopy (ATR-FTIR) and thermo-gravimetric analysis (TGA). Swelling behavior of the hydrogels was investigated at different pH and different times. The antimicrobial activity of the chitosan-graft-HEMA (CHI-HEMA) against gram-negative bacteria and gram-positive bacteria was studied by the standard agar well diffusion assay method. The CHI-HEMA 1:1 and CHI-HEMA 1:2 showed an obvious antimicrobial effect against six test strains. The CHI-HEMA 1:1 and CHI-HEMA 1:2 exhibited a highly significant increase (p < 0.01) in diameter of the inhibition zones compared with the standard antibiotics. Furthermore, CHI-HEMA 1:1 presented the highest antimicrobial activity against all test strains with a significant difference (p < 0.01) compared with CHI-HEMA 1:2. Meanwhile, the decreasing order of the average sensitivity to CHI-HEMA 1:1 and CHI-HEMA 1:2 was observed to be S. marcescens > E. coli > S. aureus subsp. aureus > S. enteritidis > E. faecalis > E. aerogenes. These results indicate potential application of CHI-HEMA 1:1 and CHI-HEMA 1:2 graft hydrogels as a novel and efficient antimicrobial agent in biomedical fields.
AtıfScopus40WoS36İncele - MakaleAçık Erişim2022Scopus SJRQ1Preparation of ε-Caprolactone/Fe3O4 Magnetic Nanocomposite and Its Application to the Remazol Brilliant Violet 5R Dye Adsorption from Wastewaters by Using RSM
Pekdemir, Mustafa Ersin; Tanyol, Mehtap; Torğut, Gülben
In this study, poly (ε-caprolactone)/Fe3O4 magnetic nanocomposite (PCL/Fe3O4 MNC) was synthesized by ring-opening polymerization. Then, PCL/Fe3O4 MNC was used as a novel adsorbent to remove remazol brilliant violet 5R (RBV 5R) from the aqueous media. The effects of PCL/Fe3O4 MNC dosage, process time, and initial RBV 5R concentration on the removal of RBV 5R were studied using the central composite design (CCD) method. The adsorption process was optimized using the response surface methodology, and the optimum conditions were defined. Optimum RBV 5R removal of 95.40% was obtained at a contact time of 167.98 min, PCL/Fe3O4 MNC dosage of 0.40 g, and RBV 5R concentration of 7.18 mg L−1. The process was also designed using the adsorption kinetic models and isotherm. The experimental data of RBV 5R adsorption on PCL/Fe3O4 MNC followed the Langmuir isotherm and pseudo-second-order kinetic models than the other models. Morphological and chemical properties of the adsorbent-adsorbate system indicated the high adsorption yield of RBV 5R on PCL/Fe3O4 MNC was achieved. The structural characteristics of the PCL/Fe3O4 MNC were analyzed by Fourier-transform infrared, attenuated total-reflectance (ATR), and X-ray diffraction. ATR tests showed that no significant change in chemical bond is found in PCL/Fe3O4 MNC before and after the adsorption process. The morphology of composites was investigated by scanning electron microscopy. A vibrating sample magnetometer (VSM) was used for the measurement of the magnetic property. Thermal analysis of MNC was studied using thermogravimetric analysis and differential scanning calorimetry instruments.
AtıfScopus6WoS5OpenAlex6İncele - MakaleYalnız künye2022Scopus SJRQ2Dielectric Biodegradable Biopolymer-Based Graphene Nanocomposites for Use in the Packaging Industry and Capacitor Application
Gürler, Nedim; Torğut, Gülben
In this study, polyhydroxyalkanoate (PHA) and polylactic acid (PLA)-Graphene (G) nanocomposite films were synthesized by taking different concentrations of G via the solution casting process, and their structural, mechanical, opacity, thermal and dielectric properties were examined for the first time. Scanning electron microscopy (SEM) was used for investigating surface morphology. Films containing graphene were more opaque than films without graphene. The incorporation of graphene into the polymer matrix improved the mechanical property. The tensile strengths of the control PHA/PLA film and the graphene-reinforced 1 %G-PHA/PLA nanocomposite films were 18.98 and 24.34 MPa, respectively. Thermogravimetric analysis results showed that PHA/PLA−G nanocomposites had good thermal stability below 300 °C. Considering the dielectric measurements, it is seen that the dielectric constant (έ) and dielectric loss (ϵ”) decreased with increasing frequency and less changed at higher frequencies. The developer feature of graphene is remarkable in both parameters. The electrical conductivity of PHA/PLA−G nanocomposites was also examined as a function of frequency at room temperature. As the amount of G increased from 1 %wt to 5 %wt, the conductivity of the composites increased.
AtıfScopus9WoS8OpenAlex11İncele - MakaleYalnız künye2021Scopus SJRQ2Graphene-reinforced potato starch composite films: Improvement of mechanical, barrier and electrical properties
Gürler, Nedim; Torğut, Gülben
In this study, PSG composite films were prepared by casting method by adding graphene (G) to glycerol plasticized potato starch (PS) films. The structure and properties of the composite films were investigated attenuated total reflectance Fourier transform infrared (ATR-FTIR), X-ray analysis (XRD), and swelling capacity, total soluble matter, transparency, tensile strength, and electrical conductivity. When the G content of PSG composite films increased from 0% to 1%, tensile strength increased from 1.035 MPa to 1.681 MPa, but decreased to 1.175 MPa in composite films containing 2% G. It also increased electrical conductivity when the G concentration increased. Also, the G layers are among the PS films and their swelling and solubility properties are reduced. With increased G concentration, the light transmittance decreased and the films were more opaque. These improvements can refer to the interface interaction between PS and G.
AtıfScopus43WoS35OpenAlex39İncele - MakaleYalnız künye2021Scopus SJRQ2Nanofiller reinforced biodegradable PHA/PLA composites: physico-chemical, thermal and dielectric properties
Torğut, Gülben; Gürler, Nedim
In this study, the electrical, thermal, morphological and physical properties of polyhydroxyalkanoate (PHA) and polylactic acid (PLA) blends and its nanocomposites prepared in different content of montmorillonite (3%wt, 5%wt, 7%wt) were investigated. Biodegradable blends of PHA/PLA were prepared in different compositions ranging from 30–70%. Nanocomposite films were analyzed by Fourier Transform Infrared (FTIR), Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA) and scanning electron microscopy for morphology (SEM). The effects of the amount of MMT used as a reinforcing filler on the morphology, color, opacity, thermal stability, and dielectric properties of PHA/PLA films were investigated. SEM analyses showed good interaction between MMT and PHA/PLA film. As the MMT concentration increases, the transparency of the films decreases. In addition, MMT has improved thermal stability. Also, the dielectric properties and electrical conductivity of nanocomposite films were studied. The measurements were performed at frequencies between 100 Hz to 10 kHz at room temperature. As the frequency increased, dielectric permittivity (έ), the dielectric loss (ε'') and the electrical conductivity (σ) decreased and remain constant at high frequencies. έ, ε'' and the σ increased with increasing MMT content.
AtıfScopus27WoS22OpenAlex28İncele - MakaleYalnız künye2020Scopus SJRQ2Modeling and optimization of indigo carmine adsorption from aqueous solutions using a novel polymer adsorbent: RSM-CCD
Torğut, Gülben; Tanyol, Mehtap; Meşe, Zeynep
A novel adsorbent was prepared via the free radical copolymerization of 2-(dimethylamino) ethyl methacrylate (DMAEMA) and acrylonitrile (AN) using 2,2′-azobisizobutyronitrile (AIBN) as an initiator at 65 °C. Poly(DMAEMA-co-AN) was characterized by FT-IR, 1H-NMR, and SEM techniques. Its thermal properties were determined by TGA and DSC. The copolymer was used to remove indigo carmine (IC) from aqueous solutions. The optimum IC removal percentage was determined to be 99.53% with poly(DMAEMA-co-AN) of 0.10 g/100 mL, contact time of 31.37 min, 46.58 mg/L initial concentration of IC using a central composite design in response surface methodology. The high maximum adsorption capacity (196.07 mg/g) proved that poly(DMAEMA-co-AN) can be used as a promising adsorbent for the removal of IC from wastewaters.
AtıfScopus20WoS19OpenAlex21İncele - MakaleAçık Erişim2020Scopus SJRQ2Synthesis, and antimicrobial and anticancer activities of sodium acrylate copolymers
Torğut, Gülben; Pıhtılı, Güzin; Erecevit Sönmez, Pınar; Erden, Yavuz; Kırbağ, Sevda
This study was designed to synthesize poly(sodium acrylate-co-N-isopropylacrylamide) via aqueous free-radical polymerization using the 2,2′-azobisisobutyronitrile initiator system at 60°C. The structural characterization of the copolymer was determined by Fourier-transform infrared spectroscopy. The polymer was synthesized in two different ratios, namely, poly(NaAc-co-NIPA1:1) and poly(NaAc-co-NIPA2:1), to investigate whether it affects their antibacterial–antifungal activities and anti-tumour effects. When the antimicrobial activities of different proportions of the copolymer extracts prepared with pure water were examined using the agar disc diffusion sensitivity test (at 120 μL: 10.8 mg/µL), it was observed that they had effect at increasing rates against all the bacteria, yeasts and dermatophyte fungi such as Staphylococcus aureus COWAN 1, Staphylococcus cohnii ATCC 29974, Bacillus megaterium DSM 32, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25922, Klebsiella pneumoniae FMC 5, Pseudomonas aeruginosa DMS 50071 SCOTTA, Candida albicans FMC 17, Candida glabrata ATCC 66032, Trichophyton sp. and Epidermophyton sp. The results of this study revealed that the obtained copolymers have significant effects on the treatment of diseases. In addition, the anti-tumour activities of the poly(NaAc-co-NIPA1:1) copolymer on human breast (MCF-7) and ovarian cancer (A-2780) cell line were specified and it was determined that high doses of the copolymer showed anti-tumour effects on both types of cancer cell lines. Also, this article reviews its antimicrobial and anticancer activities that will be of help for future scientists.
AtıfScopus3WoS3OpenAlex6İncele - MakaleAçık Erişim2020Scopus SJRQ2Electrical properties of two-armed poly(Ɛ-CL-co-BMA) composites filled with bentonite
Pihtili, Güzin; Torğut, Gülben; Biryan, Fatih
The dielectric and electrical conductivity properties of two-armed poly(Ɛ-CL-co-BMA) copolymer and adding bentonite forms were studied. The effect of the bentonite was investigated at different quantities (%3wt, %6wt, %15 wt). The measurements were performed at frequencies between 100 Hz to 10 kHz at room temperature, and the dielectric permittivity (ε′), the dielectric loss factor (ɛ″) and conductivity (σac) were calculated. ε′ and ɛ″ increased with increasing bentonite content. In addition, changes of susceptance (B) and impedance (IZI) were examined at different frequencies ranging from 100 Hz to 10 kHz in order to investigate the effect of bentonite loading. As frequency increases, (B) increases linearly, whereas IZI decreases and remains constant at high frequencies. Two-armed copolymer synthesized using ring-opening polymerization (ROP) and Atom Transfer Radical Polymerization (ATRP) and its composites prepared with bentonite were characterized by FT-IR, 1H-NMR and SEM. Thermal behaviors were examined by TGA and DSC methods and the effect of bentonite was discussed.
AtıfScopus15WoS14İncele - MakaleYalnız künye2019Scopus SJRQ1Fabrication, characterization of poly(MA-co-NIPA)-graphene composites and optimization the dielectric properties using the response surface method (RSM)
Torğut, Gülben
Poly(Maleic anhydride-N-isopropyl acrylamide poly(MA-co-NIPA) copolymer was synthesized by Free radical polymerization method. Response surface methodology (RSM) was used for optimizing the dielectric constant (έ) and dielectric loss factor (ε՛՛). The aim of this study is to determine the quantitative relationship between selected parameters (frequency, applied voltage and graphene content) at room temperature. The importance of process parameters in the model is assessed by analysis of variance (ANOVA) investigation. Our results show that, with increasing the frequency the έ and ε՛՛ of the polymers decreases, whereas voltage has no significant effect on έ and ε՛՛ of the composites. With the incorporation of graphene into poly(MA-co-NIPA) the έ and ε՛՛ considerably increased by 244% and 387% respectively. The model predicted the maximum value of the έ (13) when the frequency was set at 4506, the voltage was set at 1.45, and the graphene content was set at 14.97 wt%. Also, the RSM indicated that maximum ε՛՛ (1969) was achieved at the frequency of 512, at the voltage of 20.44, and at the graphene content of 14.76 wt%. The morphology of composites was investigated by scanning electron microscopy (SEM). SEM results demonstrated that the poly(MA-co-NIPA)-graphene composites has interconnected and they form different morphologies with the increase of GNs content. ATR tests showed that no significant change in chemical bond and crystallization is found in composites.
AtıfScopus16WoS17OpenAlex21İncele - MakaleAçık Erişim2018Scopus SJRQ2Comparative Adsorption of Different Dyes from Aqueous Solutions onto Polymer Prepared by ROP: Kinetic, Equilibrium and Thermodynamic Studies
Torğut, Gülben; Demirelli, Kadir
Poly(1,2-epoxy-3-phenoxy)propane was synthesized by ring-opening polymerization using Sn (Oct) 2 as a catalyst and benzyl alcohol as an initiator. Homopolymer’s epoxy type was acylated with chloroacetyl chloride firstly and then modified with the diethanol amine. The polymers were characterized by FT-IR and 1H - NMR. Dye adsorption properties of poly(2-phenoxy ethyl [bis(2-hydroxy ethyl)amino]acetate) were investigated by using bromocresol green (BCG), alizarin yellow (AY) and methylene blue (MB). Amounts of dye holding polymers at different times were calculated and plotted as a function of time. According to the removal results, all of the dyes reach its highest efficiency at 90 min. The effect of pH on adsorption of dyes was studied in the pH range of 2–11. Kinetic models known as pseudo-first order and pseudo-second order were used to analyze the mechanism of adsorption, and the results indicated an adsorption kinetic compatible with the pseudo-second order. The Langmuir and Freundlich isotherms were utilized to explain the adsorption equilibrium, and when it was compared with each other, it was revealed that the Langmuir isotherm model was better than Freundlich isotherm. The maximum adsorption capacities of BCG, AY and MB were 52.63, 15.87 and 31.25 mg/g, respectively. Furthermore, thermodynamic properties (Δ H∘, Δ S∘, Δ G∘) of modified polymer were investigated for the three dyes. According to the thermodynamic parameters, the adsorption of the dyes occurred spontaneously and was endothermic. The results of this study support that novel polymer, an inexpensive and effective adsorbent, could be used for dye removal from aqueous solutions.
AtıfScopus20WoS16OpenAlex24İncele - MakaleYalnız künye2018Scopus SJRQ2Effect of the novel biodegradable copolymer and soil salinity on the growth of corn plant
Torğut, Gülben; Beker Akbulut, Gülcin
Biodegradable and biocompatible poly (1,2-epoxy-3-phenoxy propane)-co-(ε-caprolactone) poly(EPP-co-ε-CL) copolymers were synthesized by ring-opening polymerization method at four different ε-CL ratios. Copolymers were characterized using Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance (1H-NMR), thermogravimetric analysis, and differential scanning calorimetry. To examine their possible applications in agriculture, germination test and growth analyses of corn plants were carried out. For this purpose, corn (Zea mays L. cv. “72 May 80”) was allowed to germinate under suitable conditions. Copolymers, 200 mM salt (NaCl) solution, and both copolymers and salt solution were applied to the plants and compared with the control groups. On the 21st day, all the plants were harvested and were stored at −80°C until analysis. Differences in growth parameters, lipid peroxidation degrees, pigment analysis, and total carbohydrate analysis were tested in order to put forward copolymer and NaCl sensitivity of the corn. Statistical analysis was carried out using the SPSS 17.0 software program and the results were compared with each other. These results showed that the copolymers both have a positive effect on the carbohydrate and malondialdehyde (MDA), a product of lipid peroxidation content as well as the chlorophyll content. Moreover, poly(EPP-co-ε-CL0.88) was more efficient than was the other copolymers in the improvement of the detrimental effects of salinity in increasing chlorophyll, carbohydrate, and MDA content, and growth of corn plants. As a result of the study, it was demonstrated that all of the investigated parameters were affected by the applications of salt and copolymers.
AtıfScopus2WoS2OpenAlex3İncele