Yazar "Ramazanoglu, Dogu" seçeneğine göre listele

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    Engineering properties of hybrid polymer composites produced with different unsaturated polyesters and hybrid epoxy
    (Elsevier, 2024) Gokce, Neslihan; Eren, Sevki; Nodehi, Mehrab; Ramazanoglu, Dogu; Subasi, Serkan; Gencel, Osman; Ozbakkaloglu, Togay
    In this study, the mechanical properties of hybrid polymer composites produced with different unsaturated polyesters and hybrid epoxy resins are investigated. The composites were produced by blending unsaturated polyester resins (i.e., orthophthalic, isophthalic, and terephthalic) and bisphenol-A-based epoxy-vinyl ester resin to produce single, binary and ternary blends. In doing this, a total of 14 different combinations were produced. The results show that the binary and ternary polymer blends tend to improve almost all the tested properties of the polymer composites. Further, the fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) results confirmed that the reason for enahcned properties is due to better crosslinking and longer chains of polymers produced in binary and ternary mixtures. The absence of peaks determining the styrene polymerization character for all mixtures also demonstrates that the polymerization reaction takes place in all mixtures. It is also believed that the binary and ternary resin mixtures have developed higher energy absorption compared to single resin composites. All of the mentioned has been achieved while the gelation temperatures of the hybrid resin mixtures were not changed significantly and they began gelation at the expected temperature values. In addition to the gelation, peak exotherm temperatures, and barcol hardness values demonstrated that all mixtures achieved sufficient curing. The result of this study is significant and point to the great potential of producing high performance polymer composites through the use of binary or ternary resin mixtures.
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    Innovative Surface Improvement of GFRC Using Hydrothermally Produced Ch-TiO2-CuO Nanohybrid Composite Additives
    (Elsevier Sci Ltd, 2024) Ramazanoglu, Dogu; Subasi, Serkan; Marasli, Muhammed
    This study examines the impact of the Ch-TiO2-CuO nanohybrid composite on the surface properties and antimicrobial effects of Glass fiber-reinforced concrete (GFRC) panels. GFRC panels are known for their durability and aesthetic compatibility, making them suitable for exterior facades and historic restoration work. However, their porosity and hydrophilic nature make them susceptible to microbial colonization, affecting their durability and visual appeal. To address this, antimicrobial nanohybrid crystals (Ch-TiO2-CuO) were developed using a hydrothermal method and incorporated into GFRC panels. This integration offers significant advantages, including reduced maintenance, long-term structural integrity, and preserved aesthetic properties. Additionally, this approach aligns with sustainability goals by enhancing the environmental friendliness of GFRC over its lifetime. The study concludes that incorporating antimicrobial agents into GFRC production supports smart city initiatives by providing long-term protection against microbial degradation while maintaining aesthetic standards, thus contributing to cleaner, safer urban environments.
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    Multifunctional GFRC composites: PEDOT: PSS-driven dielectric enhancement for energy storage and sensing applications
    (Elsevier Science Sa, 2026) Demir, Ahmet; Musatat, Ahmad Badreddin; Subasi, Azime; Ramazanoglu, Dogu; Dehgan, Haydar; Marasli, Muhammed; Gencel, Osman
    This study presents a comprehensive investigation into the development and characterization of multifunctional Glass Fiber Reinforced Cement (GFRC) composites enhanced with Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT: PSS) to impart advanced electrical properties. We systematically analyzed the influence of PEDOT: PSS concentration (0-15 wt %) and curing age on the dielectric behavior of these novel composites, evaluating their capacitance, dielectric constant, loss factor, and electrical modulus across a broad frequency range (10 Hz-10 MHz). The integration of PEDOT: PSS significantly modified the material's electrical characteristics, demonstrating concentration-dependent variations and complex relaxation mechanisms dominated by Maxwell-Wagner interfacial polarization. The optimized P2 formulation (10 wt % PEDOT: PSS) exhibited superior electrochemical performance, maintaining the highest capacitance values and achieving a peak dissipation factor (tan delta) of 0.43 +/- 0.02 at day 15, representing a 185 % enhancement over unmodified GFRC. EDX analysis confirmed successful polymer incorporation, with P2 exhibiting the highest carbon content (5.8 wt %) and sulfur content (1.8 wt %), indicating optimal dispersion. Equivalent circuit models were established and validated (R2 > 0.98), providing insights into complex charge transport mechanisms within this hybrid material. Microstructural analyses via scanning electron microscopy revealed significant morphological modifications, including the formation of crystalline and plate-like structures, while complementary FT-IR and TGA analyses confirmed polymer-cement interaction stability and thermal stability up to 450 degrees C. These findings establish fundamental design principles for creating electrically conductive cementitious materials with tunable dielectric properties, enabling strategic deployment in innovative infrastructure systems, energy storage devices, and electromagnetic shielding technologies.
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    Treatment of Fagus orientalis Surface by ZnO/TiO2/FAS-17- Based Nanoparticles
    (Kastamonu Univ, 2023) Ramazanoglu, Dogu; Ozdemir, Ferhat
    Aim of study: In this research, the surface ofFagus orientalis (beechwood) was chosen as a substrate due to its widely used strong biostructure in the wood industry. It was functionalized with ZnO, TiO2, and FAS-17 nanoparticles to enhance its service life.Material and methods: FAS-17 (Trimethoxysilane) and ammonium hexafluorotitanate were purchased from Sigma-Aldrich, and zinc borate from Etimine S.A. Methanol, ethyl alcohol, hydrochloric acid, sodium hydroxide, and zinc oxide were provided by TEKKIM. Characterization methods included FTIR, TG/DTA, XRD, SEM, and EDX. Hydrophobicity was determined by water contact angle using KSV Cam101. UV-Vis analysis used a Shimadzu UV-160 spectrophotometer, surface roughness was measured with a Marsurf M 300 device (ISO 4287), and color analysis was performed with a Datacolor Elrepho 450 X spectrometer (ASTM 2021).Main results: The thermal stability of wood was significantly improved through the hydrothermal deposition of ZnO/TiO2 nanoparticles. Additionally, hydrophobization was achieved using Triethoxy-1H,1H,1H,2H,2H,2H-perfluorodecylsilane (C14H19F13O3Si), referred to as FAS-17.Research highlights: The study demonstrated that the introduction of ZnO/TiO2 nanoparticles improved the thermal stability of wood. Furthermore, the use of FAS-17 resulted in effective hydrophobization. The thermal stability of wood was improved with ZnO/TiO2 nanoparticles. In addition, hydrophobization was supplied by FAS-17.