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ÇAKMAKÇI, EMRAH

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Fen - Edebiyat Fakültesi

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ÇAKMAKÇI

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EMRAH

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Open Access
Eugenol-DOPO: A bio-based phosphorous-containing monomer for thiol-ene photocurable thermosets
(2023-01-01) ÇAKMAKÇI, EMRAH; Özükanar Ö., ÇAKMAKÇI E., Sagdic G., Günay U. S., Durmaz H., Kumbaracı İ. V.
The adverse health and environmental effects of petroleum-based materials have become a driving force for the fabrication of bio-based monomers. In this study, we synthesized a novel bio-based reactive phosphorus-containing; eugenol-DOPO, which was prepared in one step by the reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and eugenol via Atherton–Todd reaction. Moreover, a diallyl compound was also prepared by using eugenol and piperazine. All monomers were characterized by nuclear magnetic resonance (NMR), mass, and Fourier-transform infrared (FTIR) spectroscopies. Thiol-ene photocured polysulfide thermoset networks were prepared by using these newly synthesized bio-based monomers. Thermal and thermomechanical properties of the thermosets were measured. Photo-crosslinked networks displayed over 88% gel content values. The thermal stability of the networks as well as the resulting char yields were improved as the percentage of eugenol-DOPO was increased in the formulations. The presence of N and P played a synergistic effect and the limiting oxygen index (LOI) values for the thermoset materials were enhanced. We believe eugenol-DOPO is not only a good alternative monomer for the preparation of thermally stable photocurable thermosets, but it is also a suitable bio-based additive for other polymers as well. Graphical Abstract: [Figure not available: see fulltext.].
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DOPO tethered Diels Alder clickable reactive silica nanoparticles for bismaleimide containing flame retardant thiol-ene nanocomposite coatings
(ELSEVIER SCI LTD, 2017) OKTAY, BURCU; Oktay, Burcu; Cakmakci, Emrah
The modification of nanoparticles (NPs) with functional groups that render them much more compatible with the polymeric matrices to prepare organic-inorganic hybrid materials is an active area of research. In this work, flame retardant and reactive nanosilica particles were prepared. First, nanosilica particles were coated with aminosilane and then reacted with furfural to introduce Diels Alder clickable sites. Finally, these reactive NPs were phosphorylated by reacting them with 9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide (DOPO). Different amounts of DOPO tethered Diels Alder clickable nanosilica particles (DDAS) were added to a bismaleimide resin containing thiol-ene based liquid pho-tocurable mixture. Bismaleimide acted as a crosslinker between the organic matrix and DDAS NPs. The effects of DDAS on the thermal and mechanical properties and the curing kinetics of the photocured coatings were investigated. The addition of BMI increased the Tg of the coatings from 40 to 78 degrees C with respect to the base formulation. The presence of BMI improved the distribution of DDAS NPs in the organic matrix. Moreover, the thermal and the flame retardancy of the hybrid coatings were improved. While the LOI of the base formulation was found as 21.6%, with the introduction of DDAS NPs the LOI of the hybrid coatings was increased up to 24.1%. (C) 2017 Elsevier Ltd. All rights reserved.
Open Access
Metal-free click modification of triple bond-containing polyester with azide-functionalized vegetable oil: plasticization and tunable solvent adsorption
(2022-07-12) ÇAKMAKÇI, EMRAH; Cangul K., ÇAKMAKÇI E., Daglar O., Günay U. S., Hızal G., Tunca Ü., Durmaz H.
Pressure from environmental nongovernmental organizations and the public has accelerated research on the development of innovative and renewable polymers and additives. Recently, biobased \"green\" plasticizers that can be covalently attached to replace toxic and migratory phthalate-based plasticizers have gained a lot of attention from researchers. In this work, we prepared an azide-functionalized soybean oil derivative (AzSBO) and investigated whether it can be used as a plasticizer. We covalently attached AzSBO to an electron-deficient triple-bond-containing polyester via a metal-free azide-alkyne click reaction. The thermal, mechanical, and solvent absorption behaviors of different amounts of azidated oil-containing polyesters were determined. Moreover, the plasticization efficiency of AzSBO was compared with the commercial plasticizers bis(2-ethylhexyl) phthalate and epoxidized soybean oil. At relatively lower AzSBO ratios, the degree of cross-linking was higher and thus the plasticization was less pronounced but the solvent resistance was significantly improved. As the ratio of AzSBO was increased, the glass transition temperature of the pristine polymer decreased up to 31 degrees C from 57 degrees C. Furthermore, the incorporation of AzSBO also improved the thermal properties and 20% AzSBO addition led to a 60 degrees C increase in the maximum weight loss temperature.
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New horizon in phospha-michael reaction: Ultrafast double addition of P-H bond-bearing nucleophiles to alectron-deficient triple bonds and its use for functional monomer synthesis and polymer modification
(2023-01-01) ÇAKMAKÇI, EMRAH; FINDIK, VOLKAN; ERDEM, SAFİYE; Sagdic G., Daglar O., ÇAKMAKÇI E., FINDIK V., ERDEM S., Tunca Ü., Günay U. S., Durmaz H.
In this work, a novel, straightforward, robust, fast, and organocatalyst-mediated phospha-Michael reaction (OCPMR) was developed for the addition of phosphorus nucleophiles to electron-deficient alkynes. Several P-H bond-bearing compounds with either fully aliphatic or aromatic units were utilized for this newly developed reaction, and it was found that phosphorous species containing only aromatic groups reacted with activated alkynes within 5 min at room temperature. The reaction led to a fast double-addition of the phosphorous compounds to the triple bond of the alkynes. An in-depth analysis of the reaction mechanism and selectivity of this OCPMR was performed using computational methods. Using the developed method, double-phosphorylated allyl-functional monomers were synthesized and subsequently used for the synthesis of linear and crosslinked polymers via thiol-ene photopolymerization. The thermoset materials exhibited LOI values as high as 26.4%. We also showed that polyesters having electron-deficient triple bonds could be easily functionalized with the P-H bond-bearing compounds. The synthetic method proposed herein promises easy and fast P-C bond formation under mild reaction conditions, and it is a straightforward method for the synthesis of phosphorus-containing monomers, linear or crosslinked polymers, and for polymer post-functionalization. We believe this feature will be of great interest not only to material chemists and polymer scientists but also to organic chemists, pharmaceutical researchers, etc.
Open Access
Thermal and mechanical properties of thiol-ene photocured thermosets containing DOPO-based liquid reactive flame retardant synthesized by metal-free azide-alkyne click reaction
(2022-06-01) ÇAKMAKÇI, EMRAH; Sagdic G., ÇAKMAKÇI E., Daglar O., Günay U. S., Hızal G., Tunca Ü., Durmaz H.
The use of metal-free click reactions for the design and synthesis of novel flame retardant reactive monomers for thiol-ene photopolymerization is an intriguing area of research. In this study, we have prepared a new, 9,10-dihy-dro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based, P-and N-containing reactive flame retardant via the metal-free azide-alkyne click reaction. For this purpose, first, azide-functionalized DOPO (DOPO-N-3) has been synthesized via Atherton-Todd reaction, and then this compound has been reacted with acetylene dicar-boxylic acid diallyl ester (ACDAE) to give the flame retardant monomer, namely DOPO-triazole diallyl ester (DTDAE). As prepared flame retardant monomer was characterized by nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR) spectroscopies. Thermoset materials prepared by using DTDAE displayed over 90% gel content values. Polar triazole and phosphorous units rendered the surface of the ther-mosets hydrophilic. The thermal stability of the networks was enhanced, char yields increased and the glass transition temperatures (T(g)s) were increased. The limiting oxygen index (LOI) values of the crosslinked materials increased up to 27.8% as the DTDAE content was increased in the formulations. The synthetic method described in this study provides a practical approach for the synthesis of a P-and N-containing flame retardant through a metal-free azide-alkyne click reaction Also, the fact that DTDAE is in a liquid state makes this study valuable as it indicates that it can be easily dispersed. It is also believed this promising compound can be used in different polymer structures and formulations to develop new flame retardants in future studies to be applied in industrial applications.
Open Access
Thiol-ene photopolymerization meets azide-alkyne click reactions: P/N/Si-containing, dual curable eugenol-based hybrid coatings
(2023-08-17) ÇAKMAKÇI, EMRAH; Özükanar Ö., ÇAKMAKÇI E., Daglar O., Durmaz H., Kumbaracı İ. V.
The use of bio-based building blocks for the synthesis of polymers is increasing day by day. Among the bio-based building blocks, eugenol is a highly promising monomer for the preparation of thermoset materials. In this study, we combined thiol-ene photopolymerization (TEP) and thermal azide-alkyne cycloaddition click reactions to prepare eugenol-based thermally stable, P-, N-, and Si-containing networks. To this end, we synthesized a P-containing, eugenol-based monomer bearing azide group and a siloxane compound containing an alkyne group. By mixing these monomers with multifunctional thiols and by utilizing a dual-curing strategy, we managed to obtain optically transparent and thermally stable coatings with excellent adhesion to glass substrates. Thermal stability, optical transmittance, pendulum hardness, solvent resistance, and the adhesion performance of the coatings were evaluated. The gel contents of the thermoset materials were found to be over 95%. At 600 °C, the char yields of the dual-cured coatings were found to be over 30%. Coatings were also found to be resistant to acidic and basic conditions as well as solvents.
Open Access
Propiolated castor oil: A novel and highly versatile bio-based platform for extremely fast, catalyst-, and solvent-free amino-yne click reactions
(2023-01-01) ÇAKMAKÇI, EMRAH; Celik B., Kandemir D., Lüleburgaz S., ÇAKMAKÇI E., Günay U. S., Kumbaracı İ. V., Durmaz H.
The quest for sustainable monomers and \"green\" synthetic pathways for the design, fabrication, and modification of various polymers is of great importance and attracts a great deal of attention. Here, a highly versatile and novel bio-based platform was developed by reacting castor oil with propiolic acid for performing amino-yne click reactions. Owing to the electron-deficient nature of the propiolic acid esters, amino-yne click reactions were conducted with ease at room temperature, in the absence of any catalyst and solvent (as long as the amines were low-viscosity liquids at room temperature), and within 5 min. Several primary and secondary amines were shown to react readily with the developed platform. Furthermore, thermosets were prepared by using the propiolated castor oil and multifunctional amines. The prepared thermosets displayed improved thermal properties and elastomer-like mechanical properties.
Open Access
Vegetable oil-based, coumarin-containing antibacterial thermosets with improved thermal stability via copper-free thermal azide-alkyne click polymerization
(2022-08-01) ÇAKMAKÇI, EMRAH; ÖZDEMİR, MÜCAHİT; YALÇIN, BAHATTİN; ÇAKMAKÇI E., Ozdemir M., Sen F., Bulut M., YALÇIN B.
In recent years, the preparation of thermoset materials based on renewable sources has received peculiar attention. In this work, we prepared vegetable oil based antibacterial thermosets via thermal azide-alkyne cycloaddition reactions. Dimer diamine was propargylated and mixed with azidated trimethylolpropane triglycidyl ether and castor oil bearing azide and phosphorous groups. Two different propargyl functionalized marins were also incorporated into the vegetable oil based formulations. All synthesized monomers characterized by Fourier-transform infrared (FTIR) and Nuclear magnetic resonance (NMR) spectroscopy. chanical, thermal and antibacterial properties of the obtained thermosets were also determined. The thermosets behaved as elastomers and displayed elongation at break values between 39% and 82%. The phosphorylated castor oil derivative improved the thermal properties and char yields as high as 13.83% at 750 ? were observed under nitrogen atmosphere. Coumarin-containing thermosets were found to have antibacterial activity against both gram-positive and gram-negative bacteria.
Open Access
Recent advances in flame retardant polymers via thiol-ene click chemistry
(2023-01-01) ÇAKMAKÇI, EMRAH; ÇAKMAKÇI E.
Within the toolbox of click chemistry, the utilization of thiol-ene reactions for polymer synthesis and modification is a current area of intense attention. Thiol-ene click reactions are used for a broad range of applications. One main area that needs particular attention, where thiol-ene click reactions are immensely employed, is the fabrication of coatings. Especially, when light is used to trigger the thiol-ene reactions, coatings can be prepared within seconds. This method is known as thiol-ene photopolymerization (TEP) and it is a marvelous advancement among light-induced crosslinking systems. TEP is a powerful tool for the preparation of coatings. The synthesis of phosphorous monomers for TEP has prominent importance for improved thermal properties and flame retardancy. Here, the existing literature on flame retardant TEP systems and reactive phosphorous monomers used in TEP are summarized. This review mainly highlights the studies on thermosets yet some linear polymer examples are also included. While this mini-review focuses mostly on TEP, relevant works involving other thiol-ene polymerization routes (i.e. thermal thiol-ene polymerization) rather than photopolymerization are presented. Finally, studies that utilize thiol-ene click reactions to synthesize phosphorous monomers and flame retardants are also given.
Open Access
Facile Modification of Propiolated Castor Oil via Nucleophilic Thiol-Yne Click Reactions
(2024-01-01) ÇAKMAKÇI, EMRAH; Kalayci D., Akar E., Lüleburgaz S., ÇAKMAKÇI E., Günay U. S., Kumbaracı İ. V., Durmaz H., Tunca Ü.
The combination of modern click protocols and bio-based building blocks is a great step toward energy-efficient, and sustainable polymer production. Herein, thiol-Michael addition (thiol-yne) reactions from the toolbox of click chemistry protocols are chosen and propiolated castor oil (PCO) is used, a vegetable oil derivative, as the bio-based building block for the facile functionalization of PCO with various thiols. In addition to the functionalization of PCO, hyperbranched and crosslinked polymers are also prepared. The thiol-yne click functionalization reactions of the PCO are conducted at room temperature within 5 min and in the presence of an organic catalyst. The yields are found to change between 80% and 99% depending on the type of the thiol compound. The effect of various organic catalysts is investigated, and 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) is found to be the most effective catalyst for the thiol-yne modification reactions. The hyperbranched polymer reaches 23.8 kDa (Mw) within 5 min. The findings of this paper open up new horizons for polymer researchers who work in the field of sustainable polymers and click chemistry and the presented idea here is appealing because it offers a potential strategy for fast, reliable, modular, and functional macromolecule preparation from renewable vegetable oils.