Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 41Citation - Scopus: 44Vapor Phase Solvatochromic Responses of Polydiacetylene Embedded Matrix Polymers(Royal Society of Chemistry, 2017) Tu, Meng-Che; Cheema, Jamal Ahmed; Yıldız, Ümit Hakan; Palaniappan, Alagappan; Liedberg, BoThe solvatochromic response of polydiacetylene (PDA) in the vapor phase is enabled upon incorporation with matrix polymers such as polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), polyacrylic acid (PAA), and poly-4-vinylpyridine (P4VP). The matrix polymers provide a soft/gel-like framework for accommodating photopolymerized PDA, while facilitating its conformational alternations upon interaction with preconcentrated volatile organic compounds (VOCs). The matrix polymers enabled the differentiation of VOCs owing to their varying morphology, chemical affinity and solubility in VOCs. The ratios between PDA and the matrix polymers are optimized according to the obtained solvatochromic responses evaluated in varying temperature, humidity and storage conditions. As a proof of concept, a finger-print array for differentiation of 7 VOCs is demonstrated using matrix polymer-embedded PDA. The obtained results indicate that the response time and sensitivity of the proposed methodology supersedes previous reports on solvatochromic VOC assays. Furthermore, the proposed methodology would enable differentiation of a wide range of VOCs upon incorporation of additional matrix polymers with varying sorption properties.Article Citation - WoS: 49Citation - Scopus: 52Evaluation of a Conceptual Model for Gas-Particle Partitioning of Polycyclic Aromatic Hydrocarbons Using Polyparameter Linear Free Energy Relationships(American Chemical Society, 2016) Shahpoury, Pourya; Lammel, Gerhard; Albinet, Alexandre; Sofuoglu, Aysun; Dumanoğlu, Yetkin; Sofuoğlu, Sait Cemil; Wagner, Zdenek; Zdimal, VladimírA model for gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs) was evaluated using polyparameter linear free energy relationships (ppLFERs) following a multiphase aerosol scenario. The model differentiates between various organic (i.e., liquid water-soluble (WS)/organic soluble (OS) organic matter (OM), and solid/semisolid organic polymers) and inorganic phases of the particulate matter (PM). Dimethyl sulfoxide and polyurethane were assigned as surrogates to simulate absorption into the above-mentioned organic phases, respectively, whereas soot, ammonium sulfate, and ammonium chloride simulated adsorption processes onto PM. The model was tested for gas and PM samples collected from urban and nonurban sites in Europe and the Mediterranean, and the output was compared with those calculated using single-parameter linear free energy relationship (spLFER) models, namely Junge-Pankow, Finizio, and Dachs-Eisenreich. The ppLFER model on average predicted 96 ± 3% of the observed partitioning constants for semivolatile PAHs, fluoranthene, and pyrene, within 1 order of magnitude accuracy with root-mean-square errors (RMSE) of 0.35-0.59 across the sites. This was a substantial improvement compared to Finizio and Dachs-Eisenreich models (37 ± 17 and 46 ± 18% and RMSE of 1.03-1.40 and 0.94-1.36, respectively). The Junge-Pankow model performed better among spLFERs but at the same time showed an overall tendency for overestimating the partitioning constants. The ppLFER model demonstrated the best overall performance without indicating a substantial intersite variability. The ppLFER analysis with the parametrization applied in this study suggests that the absorption into WSOSOM could dominate the overall partitioning process, while adsorption onto salts could be neglected. (Figure Presented).Article Citation - WoS: 18Citation - Scopus: 21Crystallization Kinetics and Affecting Parameters on Polycaprolactone Composites With Inorganic and Organic Additives(John Wiley and Sons Inc., 2015) Cesur, Serap; Alp, Burcu; Küçükgöksel, Yelda; Kahraman, Tansel; Balköse, DevrimThe isothermal crystallization and mechanical behavior of biodegradable polycaprolactone (PCL) composites with organic (oleic acid and glycerol monooleate) and inorganic (zinc oxide, organoclay, and hydroxy apatite) additives used alone or simultaneously were investigated. The effect of all additives on the degree of crystallinity percentage (DOC%), isothermal crystallization kinetics parameters, and mechanical test results of PCL composites was studied. The PCL composite films were prepared by solvent casting by using dichloromethane as the solvent. The films were characterized by X-ray diffraction, differential scanning calorimetry (DSC), and tensile tests. DSC of the first melting and X-ray diffraction DOC% results (for composites by solvent casting) are compatible. The values by DSC of the second melting (for composites by extrusion method) are lower. Organoclay gives the highest crystallinity among the other inorganic additives used. Small amounts of inorganic additives act as a nucleating agent and increase the crystallinity; the higher amounts decrease. The organic additives act as the plasticizer. When used alone, it lowers the crystallinity, but when used with inorganic additives, it improves the dispersion of inorganic particles in the polymer matrix. The isothermal crystallization kinetics parameters by Avrami analysis showed that crystallization was controlled by nucleation and the crystals had spherical structure. The nucleation type changed between thermal and athermal nucleation. The Pukanzky model interaction parameter B indicated that the organic additives improved the dispersion of inorganic particles in the polymer matrix. Statistically significant, eight correlations (F>6) were obtained for the crystallinity, crystallization parameters, Young's modulus, and tensile strength as a function of concentration of additives.Article Citation - WoS: 5Citation - Scopus: 6Donor- And/Or Acceptor-Substituted Expanded Radialenes: Theory, Synthesis, and Properties(American Chemical Society, 2014) Ramsaywack, Sharwatie; Karaca, Sıla; Gholami, Mojtaba; Murray, Adrian H.; Hampel, Frank; McDonald, Robert; Elmacı, Nuran; Lüthi, Hans Peter; Tykwinski, Rik R.The synthesis of donor- (D) and/or acceptor (A)-expanded [4]radialenes has been developed on the basis of readily available dibromoolefin (7), tetraethynylethene (10 and 20), and vinyl triflate (12) building blocks. The successful formation of D/A radialenes relies especially on (1) effective use of a series alkynyl protecting groups, (2) Sonogashira cross-coupling reactions, and (3) the development of ring closing reactions to form the desired macrocyclic products. The expanded [4]radialene products have been investigated by spectroscopic (UV-vis absorption and emission) and quantum chemical computational methods (density functional theory and time dependent DFT). The combined use of theory and experiment provides a basis to evaluate the extent of D/A interactions via the cross-conjugated radialene framework as well as an interpretation of the origin of D/A interactions at an orbital level.Article Citation - WoS: 47Effect of Filler Amount on Thermoelastic Properties of Poly (dimethylsiloxane) Networks(Elsevier Ltd., 2005) Demir, Mustafa Muammer; Menceloğlu, Yusuf Z.; Erman, BurakEnd-linked poly(dimethylsiloxane) (PDMS) networks were prepared in the presence of fumed silica particles with hydroxyl groups at their surfaces. The silica particles were introduced into the polymer solution prior to end-linking. Hydroxyl ended PDMS chains were end-linked via the tetra functional crosslinker, tetraethoxysilane. The filler content varied in the range 0-5 wt%. Atomic Force Microscopy was used to image and characterize the silica particles. Swelling, stress-strain and thermoelasticity experiments were performed. The temperature coefficient and the energetic part of the force in uniaxial extension are found to increase with increasing silica amount. This observation is ascribed to effects contributed possibly by the adsorption layer around the silica particles.