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Yazarlar

  • MakaleAçık Erişim2026Scopus SJRQ3
    Investigation 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 Erişim2025Scopus SJRQ2
    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.

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  • MakaleYalnız künye2025Scopus SJRQ2
    Response 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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  • MakaleAçık Erişim2025Scopus SJRQ1
    Improvement of mechanical, dynamic mechanical, and thermal properties of almond shell powder reinforced acrylonitrile butadiene styrene composites by addition of cerium oxide

    Doğan, Akar; Güneş, Çağdaş

    Currently, natural materials are gradually replacing synthetic materials in polymer composites due to factors including cost-effectiveness, sustainability, and the availability of raw materials. This study examined the variations in thermal, mechanical, and dynamic mechanical properties of acrylonitrile butadiene styrene (ABS) thermoplastic composite materials incorporating varying ratios of almond shell powder (ASP) and Cerium Oxide (CeO2). Tensile tests, three-point bending tests, dynamic mechanical analyses, and thermogravimetric analyses were conducted. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analyses were employed to assess pure ABS and nine distinct composite materials. The tensile strength, elastic modulus, and three-point bending strength of the composite material exhibited increases of 6%, 7%, and 7.5%, respectively, compared to pure ABS, with various ratios of almond shell powder and CeO2 reinforcement. Moreover, composite materials exhibit elevated glass-transition temperatures and storage moduli compared to pure ABS. Microstructure images obtained through SEM and EDS element mapping illustrate the distribution of ASP and CeO2 in ABS, influencing its mechanical and thermal properties. Highlights: Almond shell powder and cerium oxide were used as filler materials in ABS. Mechanical, morphological, and dynamic mechanical properties were investigated. Almond shell powder enhanced the mechanical properties of the ABS composite. Low cerium oxide supplementation improved the mechanical properties.

    • SDG 12 · Sorumlu Üretim ve Tüketim
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  • MakaleYalnız künye2022Scopus SJRQ1
    Graphene-reinforced novel poly(acetoxystyrene-co-glycidylmethacrylate) composites: Synthesis and optimization of dielectric behaviors using response surface methodology

    Pihtili, Güzin

    In this work, a new copolymer synthesis of Poly(acetoxystyrene-co-glycidylmethacrylate) (P[AOS-co-GMA]) by free radical polymerization (FRP) method is reported. The polymer composites (P[AOS-co-GMA]/graphene), containing different amounts of graphene, were prepared by the solution casting technique. Composites of Poly(acetoxystyrene-co-glycidylmethacrylate) loaded with 2.03 mass%, 5.00 mass%, 7.97 mass%, and 10 mass% graphene. The structure of AOS-GMA systems was characterized by fourier transform infrared, 1H-NMR and scanning electron microscopy. Thermal features were evaluated by the thermogravimetric analysis and differential scanning calorimetry. The aim of this study is to optimize the ε′ (dielectric constant) and ε′′ (dielectric loss factor) of pure polymer and graphene-doped (2.03-5-7.97-10 mass%) P(AOS-co-GMA) composite using response surface methodology. For optimization of the process and creation of the mathematical model, the central composite design package was used. The significance of the process parameters in the model was evaluated by analysis of variance (ANOVA) research. The effects of process parameters, frequency (Hz), voltage (V), and graphene ratio (mass%) on ε′ and ε′′ were examined at ambient temperature. The maximum ε″ value (8.01) was reached at around the 699 Hz frequency and at 11.43 V voltage at the graphene content of 9.82 mass%. The model estimated the maximum value of the ε′′ (0.08) when the frequency was set at 51.20, the voltage was fixed at 1.16 and the graphene content was fixed at 9.97 wt%. The ANOVA results showed that frequency and graphene content were the main model parameters and had a remarkable effect on the dielectric properties. This article presents the development of a new polymeric composite and optimize effect of process parameters, such as frequency (A), voltage (B) and amount of graphene (C).

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