Yazar "Ciftci, Mustafa" seçeneğine göre listele

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    A Novel Route to Glass Fiber-Reinforced Epoxy Matrix Composites: Visible Light Activated Radical Induced Cationic Frontal Polymerization
    (Wiley-V C H Verlag Gmbh, 2025) Kurtulus, Cenk; Ciftci, Mustafa; Tasdelen, Mehmet Atilla
    In the current study, a novel radical-induced cationic frontal polymerization (RICFP) concept capable of rapid curing at room temperature via visible light irradiation is represented. Initially, the optimal formulation, which can be most effectively cured with visible light irradiation, is determined based on thickness, hardness, curing speed, and mechanical properties using FT-IR, DSC, TGA, and flexural test methods. Subsequently, the viability of the method is illustrated by fabricating glass fiber-reinforced composites through the hand lay-up technique, employing the optimized formulation and glass fibers in various forms (chopped strand mat and biaxial). Mechanical properties of the obtained composites, including bending, tensile, and shear tests, are carried out according to relevant international standards and compared with reference composites thermally cured with amine-based hardener by conventional method. A novel visible light curable epoxy resin for glass fiber-reinforced composites is developed, combining industrial-grade epoxy resin with a photoinitiator, photosensitizer, reactive solvent, and thermal initiator. Optimal formulation is identified by evaluating thickness, hardness, curing speed, and mechanical properties. The composites produced show mechanical properties comparable to thermally cured ones. image
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    An orthogonal approach for the synthesis of graft copolymers: Visible light induced free radical polymerization and iniferter processes
    (Taylor & Francis Inc, 2024) Tulumcu, Zeynep; Akyel, Cansu; Ciftci, Mustafa
    Graft copolymers with polystyrene main and poly(ethylene glycol) methyl ether acrylate side chains are synthesized via an orthogonal approach combining visible light induced free radical polymerization and iniferter processes. The method relies on a deliberately designed, double functional monomer, 2,2,2-(triphenylethyl)styrene (TPES), containing both polymerizable and iniferter units.
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    Enhanced Mechanical Performance of Cement Paste Through Incorporation of a Tailored Terpolymer
    (Wiley, 2025) Tulumcu, Zeynep; Ozturk, Murat; Ciftci, Mustafa
    This study presents a novel approach to enhance the mechanical performance of cement pastes through the incorporation of a tailor-made terpolymer synthesized from methyl methacrylate (MMA), hydroxyethyl acrylate (HEA), and tert-butyl acrylate (tBA), which hydrolyzes into PMMA-co-PHEA-co-PAA. Unlike conventional single-polymer systems, this multifunctional terpolymer provides synergistic reinforcement by integrating hydrophobic, hydroxyl, and carboxyl functionalities. The polymer was added at 0%-0.750% by cement weight. Mechanical testing and multi-scale analyses (FT-IR, XRD, SEM, 1H-NMR) revealed a remarkable 94% increase in flexural strength at 0.750% polymer, attributed to interpenetrating polymer networks bridging micro-defects and distributing stress uniformly. Compressive strength peaked at 0.125% due to microstructural densification but declined at higher dosages because of polymer-induced porosity. These findings demonstrate a tunable balance between strength and toughness, positioning PMMA-co-PHEA-co-PAA as a next-generation polymer additive for crack-resistant, flexible cementitious materials.
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    Improving the mechanical properties of fiber-reinforced polymer composites through nanocellulose-modified epoxy matrix
    (Budapest Univ Technol & Econ, 2024) Kuyumcu, Mustafa; Kurtulus, Cenk; Ciftci, Mustafa; Tasdelen, Mehmet Atilla
    In this study, the potential use of nanocrystalline cellulose (CNC) modified epoxy nanocomposite as a matrix is investigated for both glass and carbon fiber-reinforced composites. Various amounts of CNCs (1, 2, 4, and 6 wt%) were added to bisphenol A diglycidyl ether-based epoxy resin (DGEBA), and the optimum CNC loading was determined as 4 wt% in terms of mechanical and thermal properties. Compared to the reference sample containing a neat epoxy matrix with the obtained carbon fiber/CNC-epoxy (CNC/epoxy/CF) and glass fiber/CNC-epoxy (CNC/epoxy/GF) hybrid nanocomposites, significant improvements have been determined in the in-plane shear modulus and strength, and flexural modulus, respectively. The mechanical properties improvements of CNC/epoxy/CF hybrid composites are approximately 0.9% higher than the CNC/epoxy/GF hybrid composites. Additionally, the distribution of CNC in hybrid nanocomposites is also investigated by scanning and transmission electron microscopies. It is noted that the homogenous dispersion of CNCs in the epoxy matrix and their diameters varied from 10 to 100 nm are detected at higher magnification.
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    Metal-free ATRP and ROP for graft copolymers: an orthogonal strategy for sequential and concurrent polymerizations at room temperature
    (Wiley, 2026) Akyel, Cansu; Ormanci, Ahmet; Ciftci, Mustafa
    Well-defined poly[(methyl acrylate)-co-(hydroxyethyl acrylate)]-graft-) copolymers were synthesized using a completely metal-free strategy by combining atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP) at ambient temperature. These two orthogonal, metal-free, controlled/living processes, tested in both simultaneous and sequential approaches, were employed to fine-tune grafting density and efficiency by systematically varying monomer concentration and polymerization time. Spectroscopic and chromatographic characterizations confirmed that both ATRP and ROP proceeded in a controlled fashion, yielding graft copolymers with narrowly distributed molecular weights.
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    Metal-Free, Sustainable Synthesis of Polycaprolactone-Based Graft Copolymers Through Tandem ROP and ATRP at Ambient Temperature
    (Wiley, 2026) Tulumcu, Zeynep; Zor, Ozge; Ciftci, Mustafa
    A metal-free and sustainable strategy for the synthesis of graft copolymers was developed by combining ring-opening polymerization (ROP) of epsilon-caprolactone with atom transfer radical polymerization (ATRP) at ambient temperature. Polycaprolactone (PCL) backbones bearing initiating sites were first prepared and subsequently employed for ATRP of two different vinyl monomers, methyl methacrylate (MMA) and poly(ethylene glycol) methyl ether acrylate (PEGA). This tandem polymerization approach enabled the controlled preparation of well-defined PCL-g-PMMA and PCL-g-PPEGA graft copolymers without the use of transition-metal catalysts. The successful incorporation of side chains was confirmed by 1H-NMR and FT-IR spectroscopy, while molecular weight distributions were evaluated by gel permeation chromatography (GPC). Differential scanning calorimetry (DSC) revealed the influence of grafting on the thermal properties of the copolymers, and water contact angle (WCA) measurements demonstrated surface wettability changes associated with PEGA incorporation.
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    Orthogonal synthesis and modification of hyperbranched polymers via different colors of light
    (Wiley, 2024) Kokcu, Esra; Ciftci, Mustafa; Tasdelen, Mehmet Atilla
    A versatile and straightforward approach for the synthesis of functional hyperbranched polymers with tunable properties is represented utilizing a chromatic orthogonal protocol. The method involves the combination of photo-induced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) and self-condensing vinyl polymerization (SCVP) under visible light irradiation leading to the formation of hyperbranched polymers with well-defined properties possessing photo-caged diene moieties. Upon UV light irradiation, the remaining photoenol functionality was efficiently activated for the post-functionalization of the synthesized hyperbranched polymers with maleimide functional molecules via Diels-Alder photo-click chemistry. Both low molar mass and polymeric maleimide functional click components, namely N-phenylmaleimide, poly(ethylene glycol)-maleimide and polycaprolactone-maleimide were quantitively attached onto the hyperbranched polymers under ambient conditions. The results obtained from our protocol indicate high efficiency and convenience, offering a straightforward strategy for the design and synthesis of functionalized hyperbranched polymers. The chromatic orthogonal nature of the protocol enables precise control over the modification process, adding versatility to the materials obtained. Overall, this research lays the groundwork for novel pathways in material design, opening new possibilities for advanced materials with tailored properties. image
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    Photon-powered composite fabrication: Advancing fiber-reinforced composites with light-induced systems
    (Pergamon-Elsevier Science Ltd, 2025) Ciftci, Mustafa; Tasdelen, Mehmet Atilla
    Fiber-reinforced composites (FRCs) are advanced materials combining fibers (e.g., glass, carbon, aramid) with a polymer matrix to provide high strength, stiffness, durability, and lightweight properties. Traditional FRC manufacturing methods rely on thermal curing, which involves high energy consumption (often exceeding 100 degrees C for several hours) and long processing times, increasing production costs and limiting sustainability. To address these limitations, light-induced polymerization has emerged as a promising alternative. Light-induced polymerization, a process in which monomers are transformed into polymers through photoinitiators, offers spatial and temporal control, significantly reducing curing times to minutes while minimizing energy consumption. Unlike thermal curing, this method enables precise polymerization using various wavelengths of light, from UV to visible range, while reducing the need for toxic chemicals or solvents. Studies have demonstrated that UV-cured FRCs can achieve mechanical properties comparable to thermally cured composites, depending on the fiber content and resin formulation. Recent advancements, such as stepwise UV curing and radical-induced cationic frontal polymerization (RICFP), have improved light penetration, enabling uniform polymerization even in thick laminates (up to 20 mm). However, challenges such as limited light penetration due to fiber absorption and optical interference remain key barriers to widespread adoption. This review uniquely consolidates recent advancements in light-induced polymerization for FRC fabrication and critically evaluates strategies to overcome these challenges, including photoinitiator selection, diluent optimization, and wavelength tuning. By systematically discussing the role of photoinitiators, fiber types, fillers, and irradiation wavelengths, this work provides novel insights into the chemistry, processing strategies, and future directions of this emerging technology.
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    Synthesis of Graft Copolymers by Combination of PET-RAFT and Ring Opening Polymerization at Ambient Temperature
    (Wiley-V C H Verlag Gmbh, 2025) Akyel, Cansu; Ciftci, Mustafa
    Well-defined poly(methyl acrylate-co-hydroxyethyl acrylate)-graft-poly(epsilon-caprolactone) (PMA-g-PCL) copolymers were successfully synthesized via a combination of photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) and ring-opening polymerization (ROP) under ambient conditions. Initially, random copolymers of methyl acrylate (MA) and 2-hydroxyethyl acrylate were prepared through PET-RAFT polymerization. These copolymers, bearing pendant hydroxyl moieties, subsequently served as macroinitiators for the grafting of poly(epsilon-caprolactone) side chains via ROP. The influence of monomer concentration in feed and polymerization time on grafting density and efficiency was investigated. Structural and molecular characterization of both the precursor copolymers and the final graft copolymers was conducted by 1H-NMR, FT-IR, and GPC analysis. The combined spectroscopic and chromatographic results confirmed that both PET-RAFT and ROP proceeded in a controlled manner, resulting in graft copolymers with well-defined architectures and narrow molecular weight distributions.
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    Synthesis of hyperbranched polymers by combination of self-condensing vinyl polymerization and iniferter process
    (Wiley, 2023) Guner, Samet; Ciftci, Mustafa
    A versatile approach for the synthesis of polystyrene based hyperbranched polymers (hyp-PS) with tunable branching densities by combination of self-condensing vinyl polymerization and iniferter processes is reported. The technique is based on the utilization of a dual functional monomer, 2,2,2-(triphenylethyl)styrene (TPES), that contains both polymerizable and iniferter units. Branching densities of the polymers are regulated depending on the TPES concentration and polymerization time. Moreover, obtained polymers are used as macroiniferter for the copolymerization of a hydrophilic monomer (poly(ethylene glycol) acrylate) to give amphiphilic branched-core star polymers.