Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025Scopus SJRQ2/r/munzur/1061
  Effect of Nano Titanium Dioxide on the Electrical and Thermal Properties of Poly(2,2,2-Trifluoroethyl Methacrylate) for Dielectric Materials

  Barım, Esra; Torgut, Gülben

  The increasing application areas of energy storage devices in recent years make it necessary to produce materials with sufficient efficiency. In this study, composites of poly(2,2,2-trifluoroethyl methacrylate) P(TFEM) homopolymer with nano titanium dioxide (TiO2 NPs) were prepared for applications of these devices requiring thermoelectric properties, and their thermal, dielectric, and electrical properties were investigated. Thermogravimetric analysis showed that TiO2 NPs in all composites limited the thermal diffusion of TiO2 NPs in the polymer matrix and increased the thermal stability of P(TFEM) from 341°C to 361.5°C. As dielectric properties, the dielectric constant (ε′), dielectric loss (ε″), AC conductivity (σac), and real (Z′) and imaginary (Z″) components of impedance of the composites containing TiO2 NPs were evaluated as functions of frequency and different weight percentages of TiO2 NPs. Increases in ε′ and ε″ at up to 15 wt% TiO2 NPs suggested increased dipole polarization. At 100 Hz, the ε″ value of P(TFEM) increased from 3.2 × 10−2 to 1.1 × 10−2, σac increased from 4.98 × 10−10 to 1.00 × 10−8, Z′ increased from 3.67 × 1010 to 8.66 × 1010, and Z″ increased from 2.09 × 108 to 4.42 × 108. Furthermore, ε′, ε″, and impedance decreased with increasing frequency for both P(TFEM) and TiO2 NPs composites, while σac increased with increasing frequency.

  AtıfScopus3·OpenAlex5

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• MakaleAçık Erişim2025Scopus SJRQ2/r/munzur/991
  PCL/chitosan composite films enhanced with Bi2O3 in nuclear shielding applications: Irradiation resistance, thermal and structural properties

  Yılmaz, Demet; Pekdemir, Mustafa Ersin; Dik, Gamze; Selçuk Pekdemir, Sibel; Ulu, Ahmet; Taşgın, Yahya; Ateş, Burhan

  In this work, irradiation resistance, thermal, and structural characteristics of Bi2O3-reinforced poly ε-caprolactone/chitosan composites for nuclear shielding applications were studied. PCL/CTS/Bi2O3 composite films were prepared by using different amounts of Bi2O3 (0.5%–4.0% (w/v)). The radiation shielding parameters of the synthesized composite films were both experimentally and theoretically measured at the high energy region. The equivalent dose rates of the prepared film samples were measured using a fast neutron source. Also, to determine the irradiation resistance, the samples were irradiated with Am-241 and Co-60 sources for 30 days. The MFP values at 80.99 keV changed by approximately 61% in samples PCL/CTS and PCL/CTS/4% Bi2O3. The results show that Bi2O3 content increases the gamma shielding abilities in PCL/CTS films. According to TGA results, the thermal stability of the polymer composite films is increased by the addition of Bi2O3 to the PCL/CTS blend film. The results show that PCL/CTS composite materials can be used as protective coating materials for nuclear shielding. Highlights: PCL/CTS/Bi2O3 composite films were prepared by the solvent casting method. The thermal stability of the composite films increased by increasing the Bi2O3 amount. Bi2O3 increased the LAC and MAC values of the composite films. PCL/CTS/Bi2O3 composite films have a neutron shielding effect.

  AtıfScopus5·WoS5

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• MakaleYalnız künye2024Scopus SJRQ2/r/munzur/2176
  Evaluation of effect of boric acid on thermoplastic starch: Morphological, mechanical, barrier, and optical properties

  Yoğurtçu, Hakan; Gürler, Nedim

  In this study, starch was modified with different amounts of boric acid, and the degree of substitution of the synthesized compounds at different temperatures and times was determined by Fourier transform infrared (FTIR) and titration methods. The degrees of substitution in both methods showed similar tendency. Optimum conditions were determined, and thermoplastic starch (TPS) and boric acid (B) films were prepared by casting method using glycerol as plasticizer. The morphological properties of the films were studied by scanning electron microscope-energy dispersive spectrometry (SEM-EDS). According to the FTIR results, it was observed that the B-O and B-O-C stretching vibrations increased when the amount of boric acid increased. The tensile strength, water barrier (swelling capacity, solubility, and water vapor permeability), and optical properties of samples were investigated. The swelling capacity, solubility, and water vapor permeability of the films decreased with the addition of 0.5% boric acid to the starch, but the highest tensile strength was achieved. The tensile strength for TPSB0.5% increased compared to control group TPS. In addition, the film showed the highest transparency. Thermoplastic film containing 0.5% boric acid can be used as a packaging material due to its improved mechanical and water barrier. Highlights: The thermoplastic starch and boric acid composite were successfully produced. The presence of boric acid was confirmed by energy dispersive spectrometry (EDS). The degree of substitution was determined by two different methods. Transparency increased with the addition of boric acid. Tensile strength improved with boric acid content.

  AtıfScopus26·WoS25·OpenAlex27

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• MakaleYalnız künye2023Scopus SJRQ2/r/munzur/2920
  Development of chitosan/gelatin/starch composite edible films incorporated with pineapple peel extract and aloe vera gel: Mechanical, physical, antibacterial, antioxidant, and sensorial analysis

  Gürler, Nedim

  In this study, chitosan (C)/gelatin(G)/starch(S) composites incorporated pineapple peel extract (PPE) and aloe vera gel (AVG) were prepared by the casting method as antioxidant agents. Mechanical, water vapor permeability (WVP), moisture content, solubility, opacity, and color properties of the effects of PPE and AVG at different concentrations (0%, 10%, and 30%) were investigated. The prepared films were characterized by Fourier transform infrared spectroscopy in attenuated total reflection (ATR-FTIR), X-ray diffraction (XRD), Thermal gravimetric analysis (TGA), Scanning electron microscope (SEM), mechanical, water barrier, opacity, and color. PPE and AVG extract incorporated edible films improved thermal stability of edible films. Tensile strength decreased with the addition of extracts; the maximum tensile strength was 8.15 MPa for CGS film. The WVP of the films increased with the increasing PPE and AVG concentration. As a biological activity, the films inhibited the growth of gram-positive (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli). With the addition of PPE and AVG to the CGS film, its antioxidant properties were enhanced. In addition, the prepared films were applied for strawberry coating both in the refrigerator and at room temperature. Consequently, these edible-coated films can be used for active food packaging/coating to extend the shelf life of fruits.

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  AtıfScopus51·WoS46·OpenAlex49

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• MakaleAçık Erişim2022Scopus SJRQ2/r/munzur/2865
  Synthesis, 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.

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  AtıfScopus1·WoS1·OpenAlex1

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• MakaleYalnız künye2022Scopus SJRQ2/r/munzur/2426
  Synthesis, 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.

  AtıfScopus40·WoS36

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