Yazar "Çiftci, Mustafa" seçeneğine göre listele

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    In-situ preparation of halloysite nanotube-epoxy thermoset nanocomposites via light-induced cationic polymerization
    (Elsevier Ltd, 2021) Bekin Acar, Seda; Çiftci, Mustafa; Bouharras, Fatima Ezzahra; Raihane, Mustapha; Tasdelen, Mehmet Atilla
    In the present study, homogeneous mixtures of halloysite nanotubes (HNTs)-epoxy nanocomposites are prepared through chemical treatments. Naturally present halloysite nanotubes (HNT) are primarily modified by 3-(glycidyloxypropyl)trimethoxysilane and subsequently utilized as nanofillers in a mixture of bisphenol A diglycidyl ether and trimethylolpropane triglycidyl ether by varying weight % of modified HNT from 0 to 8%. Photoinitiated cationic crosslinking polymerization of this mixture facilitates the in-situ preparation of HNT/thermoset nanocomposites at room temperature. The covalent attachment of HNT in the thermoset matrix has been confirmed by monitoring the characteristic signals of the mixture, nanofiller, neat thermoset, and final nanocomposite using fourier transformed infrared (FT-IR) spectroscopy. Furthermore, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses proved the existence and distribution of HNT in the thermoset nanocomposites. Indeed, a combination of agglomerated/non-agglomerated HNTs in the thermoset matrix is also determined. On the other hand, mechanical properties of nanocomposites are significantly improved with increase in HNT loading up to 4% ratio. Adding 4% of modified HNT into epoxy increased its tensile strength and elasticity modulus by 6.9 times and 2.3 times than the corresponding neat epoxy thermoset, respectively, without scarifying thermal stability. Therefore, the HNT/epoxy thermoset nanocomposites are suitable candidates for various applications as an alternative of expensive carbon nanotube containing analogues.
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    Influence of POSS nanoparticles on the microstructure and mechanical properties of carbon fiber reinforced epoxy hybrid composites
    (John Wiley and Sons Inc, 2021) Kurtulus C.; Kuyumcu M.; Çiftci, Mustafa; Tasdelen M.A.
    The possibility to design composites with superior properties by incorporation of nanoscale reinforcing material still remains to be fulfilled. In the current study, bisphenol A diglycidyl ether-based epoxy resin has been successfully modified with polyhedral oligomeric silsesquioxane (POSS) nanoparticles to give epoxy/POSS nanocomposites. Carbon fiber reinforced composites with different fiber orientations are processed via vacuum bagging technique using this composite as the matrix. Scanning electron microscopy indicated that POSS nanofillers homogeneously distributed in the matrix. As proved by the tensile, flexural, and interlaminar shear strength tests, the inclusion of POSS nanofillers in the polymer matrix has promoted significant improvements in the mechanical properties of the carbon fiber reinforced POSS/epoxy hybrid composites compared to the analogues with neat epoxy matrix. Thus, hybrid composites with exceptional properties are obtained via a straightforward modification in the matrix and a novel paradigm without using any expensive compound has been added to the library of nanocomposite formulations.
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    Synthesis and characterization of bile acid-based polymeric micelle as a drug carrier for doxorubicin
    (John Wiley and Sons Ltd, 2021) Altinkok C.; Acik G.; Karabulut H.R.F.; Çiftci, Mustafa; Tasdelen M.A.; Dag A.
    In the present study, a polymeric micelle based on amphiphilic block copolymer, namely poly(methacrylated methyl lithocholate)-block-poly(oligoethylene glycol methacrylate) (PMML-b-POEGMA) bearing bile acid moiety is prepared via sequential photo-initiated free radical polymerizations, and its drug carrying capacity is investigated using doxorubicin hydrochloride (DOX) as a model drug. For this purpose, two-step procedure is applied in the presence of phenylbis (2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) as bifunctional photo initiator. Based on spectroscopic and chromatographic analyses, the desired amphiphilic block copolymer (PMML-b-POEGMA) is successfully synthesized by wavelength-selective free radical photopolymerization under mild conditions. Finally, the DOX drug is loaded into the PMML-b-POEGMA micelles and then drug release behavior is investigated at two different pH (5.5 and 7.4) values. It is concluded from the results that PMML-b-POEGMA micelles may be used as an efficient nanocarrier to deliver conventional anti-cancer drugs for combination chemotherapy.