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Öğe Antibacterial film from chlorinated polypropylene via CuAAC click chemistry(Elsevier Science Bv, 2018) Acik, Gokhan; Altinkok, Cagatay; Olmez, Hulya; Tasdelen, Mehmet AtillaPolypropylene possessing quaternary ammonium salt (PP-QAS) is synthesized by copper (I)-catalyzed azide-alkyne cycloaddition "click" reaction (CuAAC) starting from chlorinated polypropylene (PP-Cl). The antibacterial properties of PP-QAS have been investigated on gram-positive (Staphylococcus aureus) and gram-negative (Escherichia colt) bacteria. For this purpose, clickable azide functionality has been introduced into PP-Cl backbone by using azidotrimethylsilane (TMS-N-3) - tetrabutylammonium fluoride solution (TBAF) system in tetrahydrofuran (THF) (PP-N-3). Independently clickable alkyne functionalized QAS is prepared by the reaction between 3-dimethylamino-1-propyne and benzyl bromide in the presence of triethyl amine (TEA). Finally, the polypropylene film containing quaternary ammonium salt (PP-QAS) is prepared by the successive CuAAC click reaction and solution casting method. The preparation of PP-QAS is monitored by fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (H-1-NMR), differential scanning calorimetry (DSC) and scanning electron microscope (SEM) analyses at various stages. Based on antibacterial activity experiments, the PP-QAS coupons significantly inhibit both the growth of S. aureus and E. coli (p < 0.05) compared to neat PP-CI and control samples.Öğe Bile acid bearing poly (vinyl chloride) nanofibers by combination of CuAAC click chemistry and electrospinning process(Elsevier, 2020) Altinkok, Cagatay; Karabulut, H. R. Ferhat; Tasdelen, M. Atilla; Acik, GokhanThis study aims to deposit most common bile acids such as lithocholic acid (LCA) and chenodeoxycholic acid (CDCA) bearing poly (vinyl chloride) nanofiber (PVC-LCA and PVC-CDCA) coatings on glass slides surface using a combination method by employing copper (I)-catalyzed azide-alkyne cycloaddition 'click' reaction (CuAAC), followed by electrospinning process. The resulted nanofibers and their intermediates are characterized by spectroscopic (FT-(IRH)-H-1-NMR), thermal (TGA and DSC), wettability (WCA) and morphological (SEM) analyses. Many characterizations reveal that the bile acid functionalized PVC-LCA and PVC-CDCA are successfully achieved by CuAAC between azido-functional PVC (PVC-N-3) and alkyne end-functional LCA and CDCA (LCAA-lkyne and CDCA-Alkyne) and their nanofibers obtained by electrospinning show efficiently improved thermal behavior, hydrophilicity and morphological features compared to pristine PVC or their granule analogues. Furthermore, the SEM images indicate that the formation of nanoscale, uniform, cylindrical and smooth fibers without free beads. The changeable properties achieved are attributed to the presence of rigid steroid skeleton, triazole rings and free -OH groups on the final polymers. Hence, it is clear that this facile combination procedure is encouraging for scientists working on potential biomedical PVC applications.Öğe Cysteamine-functionalized silver nanowires as hydrogen donor for type II photopolymerization(Elsevier Science Sa, 2017) Altinkok, Cagatay; Oytun, Faruk; Basarir, Fevzihan; Tasdelen, Mehmet AtillaA versatile method for the in-situ preparation of poly(methyl methacrylate)/silver nanowire (PMMA/AgNW) nanocomposites has been reported. The use of cysteamine-functionalized silver nanowires as hydrogen donors in type II photopolymerization enables us to fabricate PMMA/AgNW nanocomposites under mild conditions such as ambient temperature and solvent-free formulation. The morphology of nanocomposites is investigated by using scanning electron microscopy and compared by a solution mixing sample that prepared identical experimental condition. The distribution of AgNWs in the in-situ prepared nanocomposite is much homogenous than the solution mixing sample. The results from thermogravimetric analysis and differential scanning calorimetry clearly indicated that thermal behaviour of the nanocomposites is slightly improved than that of neat PMMA. (C) 2017 Elsevier B.V. All rights reserved.Öğe A facile approach for the fabrication of antibacterial nanocomposites: A case study for AgNWs/Poly(1,4-Cyclohexanedimethylene Acetylene Dicarboxylate) composite networks by aza-Michael addition(Pergamon-Elsevier Science Ltd, 2022) Altinkok, Cagatay; Acik, Gokhan; Daglar, Ozgun; Durmaz, Hakan; Tunc, Ilknur; Agel, EsraNanotechnological improvements allow the production of new generation materials among which nanocomposite-based polymers are increasingly applied for wide variety of applications due to the demand increment of improving life quality of mankind. This article describes a simple, facile and fast route which could be adopted for the synthesis of metal nanocomposite materials with a variety of polymers. In this purpose, the cysteamine compound containing an amine (NH2) and a thiol (-SH) functional groups was incorporated onto silver nanowires (NH2-AgNWs). Next, poly(1,4-Cyclohexanedimethylene Acetylene Dicarboxylate) (PCA) possessing electron deficient internal alkyne moiety is synthesized starting from acetylene dicarboxylic acid (ADCA). Finally, one-pot aza-Michael addition is then realized between prepared NH2-AgNWs and synthesized PCA to achieve a series of cross-linked antibacterial nanocomposite networks (PCA:NH2-AgNWs = 1; 5; 10 wt%). The nanocomposites and intermediates are fully characterized by Fourier transform infrared and proton nuclear magnetic resonance (FT-IR, 1H NMR) spectroscopies, gel permeation chromatography (GPC) scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), thermogravimetric and differential scanning calorimetry analyses (TGA and DSC) and antibacterial test. The results reveal that the higher content of AgNWs in the network has occasioned the enhancement in thermostability and glass transition temperature. The antibacterial efficacy tests against Escherichia coli (E. coli, G) and Staphylococcus aureus (S.aureus, G +) further indicate that higher rate of inhibition is attained for nanocomposite network including 10 wt% AgNWs compared to others and pristine PCA. Consequently, a polyester based AgNWs/PCA nanocomposite with antibacterial activity has been considered as a versatile candidate for various promising nanocomposite applications.Öğe A new strategy for direct solution electrospinning of phosphorylated poly (vinyl chloride)/polyethyleneimine blend in alcohol media(Pergamon-Elsevier Science Ltd, 2023) Altinkok, Cagatay; Sagdic, Gokhan; Daglar, Ozgun; Ayra, Merve Ercan; Durmaz, Yasemin Yuksel; Durmaz, Hakan; Acik, GokhanPhosphorylated poly(vinyl chloride) (PPVC)/polyethyleneimine (PEI)-based nanofibers were produced via electrospinning in their blended solutions for the first time. For this purpose, PVC was partially converted into PVC-N3 and the PVC-N3 is then reacted with bis(diethoxyphosphoryl) acetylene (BDPA) via metal-free azide--alkyne 1,3-dipolar cycloaddition reaction to achieve the alcohol-soluble PPVC. PPVC and PEI solutions at certain concentrations prepared in methanol were electrospun from a single syringe at 90/10 and 85/15 vol ratios without phase separation. The accuracy of the modifications conducted on PVC was proven by Fourier-transform infrared (FT-IR), proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR) spectros-copies and gel permeation chromatography (GPC), respectively. The achieved nanofibers and their intermediates were characterized by scanning electron microscope (SEM), water contact angle (WCA) measurement, ther-mogravimetric (TGA) and differential scanning calorimetry (DSC) analyses.The blood interaction of PPVC-PEI was evaluated through hemolysis and platelet activation assay, since most of the biomedical applications of PVC derivatives have close contact with blood. The results showed that PPVC-PEI nanofibers provide a safer surface for platelet with lower hemolytic activity compared to PPVC nanofibers. Therefore, PPVC-PEI-based electrospun nanofibers obtained by such an effective strategy exhibited a promising perspective for scientists in various biomedical purposes.Öğe Polypropylene microfibers via solution electrospinning under ambient conditions(Wiley, 2019) Acik, Gokhan; Altinkok, CagatayUniform beadless fibers of chlorinated polypropylene (PP-Cl) are prepared by electrospinning of PP-Cl solutions in tetrahydrofuran at different concentrations, feed rates, applied voltages, and tip-to-collector distances (TCDs) under ambient conditions for the first time. Average fiber diameter and morphology of the electrospun PP-Cl fibers are determined by scanning electron microscopy. On the other hand, the wettability of the fibers is examined by water contact angle (WCA) measurements. Furthermore, thermal behavior of fibers is investigated by differential scanning calorimetry and thermogravimetric analyses, respectively. Obtained results show that the higher concentrations and feed rates of polymer solutions not only enhance the average diameter of the electrospun fibers ranging from 2.2 +/- 0.5 to 2.8 +/- 0.3 mu m but improve the hydrophobicity of the fiber surfaces from 128 degrees +/- 1.1 to 141 degrees +/- 1.0 as well. On the other hand, when applied voltage is increased or TCD is decreased, diameters of achieved fibers are enhanced. It is suggested that PP-Cl is an useful material for solution electrospinning process at under ambient conditions, exhibiting great scientific merit and good industrial expectation in the potential PP applications. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48199.Öğe Synthesis and characterization of bile acid-based polymeric micelle as a drug carrier for doxorubicin(Wiley, 2021) Altinkok, Cagatay; Acik, Gokhan; Karabulut, Huseyin Riza Ferhat; Ciftci, Mustafa; Tasdelen, Mehmet Atilla; Dag, AydanIn 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.Öğe Synthesis and characterization of biodegradable polyurethanes made from cholic acid and L-lysine diisocyanate ethyl ester(Elsevier Sci Ltd, 2019) Acik, Gokhan; Karabulut, Huseyin Riza Ferhat; Altinkok, Cagatay; Karatavuk, Ali OsmanIn this work, a series of biodegradable polyurethanes (PURs) based on cholic acid (CA) and L-lysine diisocyanate ethyl ester (L-LDI) that are renewable difunctional building blocks is synthesized by step growth polymerization. Step-growth polymerizations between CA and L-LDI are conducted at different loading ratios by mole ([CA]/[L-LDI] (n/n) = 1:1; 1:2 and 1:4) to investigate the effect on wettability, thermal, and biodegradable properties of final PURs. The intermediates and resulting PURs are characterized by Fourier transform infrared spectroscopy (FT-IR), water contact angle measurements (WCA), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Moreover, biodegradability of obtained PURs is also investigated by conducting enzymatic degradation experiments. The experimental results reveal that PURs having higher L-LDI loading exhibit higher hydrophobic and thermal properties, while lower biodegradable characteristic compared to others. Thus, it is clear that the obtained PURs have great potential for several applications particularly in the fields of drug delivery and tissue engineering requiring biodegradable properties. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Synthesis and characterization of polypropylene-graft-poly(l-lactide) copolymers by CuAAC click chemistry(Wiley, 2018) Acik, Gokhan; Altinkok, Cagatay; Tasdelen, Mehmet AtillaThe syntheses of polypropylene-graft-poly(l-lactide) copolymers (PP-g-PLAs) via copper (I)-catalyzed azide-alkyne cycloaddition "click" reaction (CuAAC) using azide side-chain functionalized polypropylene (PP-N-3) and alkyne end-functionalized poly(l-lactide) (PLA-Alkyne) were reported. The CuAAC was then applied to azide and different feeding ratios of alkyne functional polymers to give PP-g-PLAs that were characterized by FTIR, H-1-NMR, GPC, DSC, and WCA measurements. The CuAAC click reaction was achieved by two different feeding ratio (PP-N-3:PLA-Alkyne = 1:5 and 1:10) and thermal, biodegradable, and surface properties of obtained graft copolymers were investigated. The molar ratio of PLA were calculated as 72.7 (PP-g-PLA-1) and 78.4% (PP-g-PLA-2) by H-1-NMR spectroscopy. The water contact angle (WCA) values of PP-g-PLA-1 (81(o) +/- 1.3) and PP-g-PLA-2 (75(o) +/- 1.6) copolymers were compared with commercial chlorinated polypropylene (PP-Cl) (90(o) +/- 1.0), suggesting a more hydrophilic nature of desired graft copolymers produced. Conversely, the enzymatic biodegradation studies revealed that the weight losses of graft copolymers were determined as 13.6 and 22.1%, which is about 4% for commercial PP-Cl sample. Thus, it was clear that this simple and facile method was effective in promoting biodegradation of commercial polypropylene and attractive particularly for worldwide environmental remediation goals. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2595-2601Öğe Synthesis and Properties of Soybean Oil-based Biodegradable Polyurethane Films(ELSEVIER SCIENCE SA, 2018) Acik, Gokhan; Kamaci, Musa; Altinkok, Cagatay; Karabulut, H. R. Ferhat; Tasdelen, Mehmet AtillaIn this study, a series of biodegradable polyurethane films (PU-Fs) is prepared by step-growth polymerization of hydroxylated soybean oil (SBO-OH) and L-lysine diisocyanate ethyl ester (L-LDI) that are renewable-based di-functional building blocks. The influence of loading ratio by weight (SBO-OH/L-LDI (w/w) = 1:0.5; 1:1 and 1:1.5) on the biodegradable, mechanical and thermal properties of final PU-Fs is systematically investigated. In the first step, epoxy groups of epoxidized soybean oil are converted to corresponding hydroxyl functionalities to react with the diisocyanate groups of L-LDI via film casting method at room temperature. The obtained PU-Fs with higher L-LDI loading exhibit higher thermal and mechanical properties as well as more hydrophobic characteristic compared to others. Moreover, biodegradability of resulting PU-Fs is also studied using hydrolytic and enzymatic degradation experiments. Noteworthy, it is found that around 50 and 60% of PU-Fs are degraded by enzymatic and hydrolytic experiments after 12 weeks.Öğe Synthesis of new bio-based hydrogels derived from bile acids by free-radical photo-polymerization(Wiley, 2021) Karabulut, Huseyin Riza Ferhat; Mert, Berk; Altinkok, Cagatay; Karatavuk, Ali Osman; Acik, Gokhan; Turkyilmaz, MuratIn this article, the study on the swelling and thermal behaviors of a new series of bile acid-based polymeric hydrogels is reported. For this purpose, in the first step, the reduction of carboxyl acid groups of some common bile acids including cholic acid (CA), chenodeoxy cholic acid (CDCA), and lithocholic acid (LCA) to the corresponding alcohols by lithium aluminum hydride (LiAlH4) in THF solution is performed. Then, hydroxyl functionalities of the obtained products are reacted with the acryloyl chloride in the presence of triethylamine (TEA). Finally, the cross-linking reactions between acryloyl functionalized bile acids and methoxy poly(ethylene glycol) monomethacrylate (MPEGMA) are conducted by free-radical photo-polymerization technique at lambda = 350 nm in the presence of 2,2-Dimethoxy-2-phenylacetophenone (DMPA) as an initiator to achieve the desired bile acid-based polymeric hydrogels. The resulting hydrogels and their intermediates are characterized by Fourier transform infrared (FT-IR) and Proton nuclear magnetic resonance (H-1-NMR) spectroscopies. The swelling and thermal behavior of the obtained hydrogels indicates that the hydrogel starting from cholic acid is more swellable and has enhanced thermostability compared to others. Thus, the results of this study offer beneficial insights to researchers working in particularly bio-medical industry.
