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Cellulose - The pressure retarded osmosis (PRO) process requires high performance, high flux, high rejection, and resistant membranes under harsh conditions. Since conventional phase-inversion... 相似文献
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Sean W. Ewart Thomas W. Karjala Mehmet Demirors 《Journal of polymer science. Part A, Polymer chemistry》2017,55(5):861-866
The use of post‐metallocene bis‐phenylphenoxy catalysts to polymerize ethylene under high ethylene pressures (>25,000 psi) results in some remarkable catalytic properties. The high ethylene pressure produces molar ethylene concentrations in the reactor as much as 40 times higher than in typical low pressure ethylene polymerizations. This high ethylene concentration results in high catalyst efficiency at high temperatures and low reactor residence time, between 180 °C and 240 °C the catalyst efficiency surprisingly increases with increasing temperature, allowing for use of these catalysts at temperatures much higher than can be utilized in the low pressure processes. It has further been demonstrated that under these conditions increasing hydrogen levels up to 0.5 mol% does not significantly affect the polymer molecular weight; however, polymer molecular weight control can be realized with varying reactor temperature. The polymer produced is shown to be high density polyethylene made from a single site catalyst and not free radical initiated low density polymer. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 861–866 相似文献
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Preparation of fluorinated methacrylate/clay nanocomposite via in‐situ polymerization: Characterization,structure, and properties 下载免费PDF全文
Mohamed Karamane Mustapha Raihane Mehmet Atilla Tasdelen Tamer Uyar Mohamed Lahcini Mohamed Ilsouk Yusuf Yagci 《Journal of polymer science. Part A, Polymer chemistry》2017,55(3):411-418
Novel fluorinated coating containing well‐dispersed silicate nanolayers is successfully produced via in‐situ free radical polymerization of 2,2,2‐trifluoroethyl methacrylate in the presence of vinylbenzyl‐functionalized montmorillonite with different loading. The organic modification of sodium montmorillonite is achieved through an ion exchange reaction with triphenylvinylbenzylphosphonium chloride as surfactant prepared before use by reaction with vinylbenyl chloride and phosphine. The following in‐situ polymerization in the presence of organomodified clay leads to fluorinated nanocomposites with of partially exfoliated and intercalated morphologies, as determined via XRD and TEM analysis. The nanoscale dispersion of clay layers is also evidenced by thermal analysis; a moderate decrease of the glass transition temperature about 2–8 °C compared to their virgin PMATRIF and an improvement of their thermal stability as evidenced by TGA. The wettability of the nanocomposite films is also studied by contact angle measurements with water. The incorporation of organomodified clays not only increases the hydrophobicity of the fluorinated polymers but also improves the surface properties of obtained nanocomposites. Compared the virgin homopolymer, the mechanical properties of the nanocomposites are reduced by addition of organomodifed clay at temperature from 30 to 60 °C, whereas this trend is gradually decreased at higher temperature. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 411–418 相似文献
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Mehmet Nail NasirFrançoise Besson 《Journal of colloid and interface science》2012,387(1):187-193
Bacillomycin D is a natural antimicrobial lipopeptide belonging to the iturin family. It is produced by Bacillus subtilis strains. Bacillomycin D is characterized by its strong antifungal and hemolytic properties, due to its interaction with the plasma membrane of sensitive cells. Until now, only few limited analyses were conducted to understand the biological activities of bacillomycin D at the molecular level. Our purpose was to analyze the conformation of bacillomycin D using IR spectroscopy and to model its interactions with cytoplasmic membranes using Langmuir interfacial monolayers. Our findings indicate that bacillomycin D contains turns and allow to model its three-dimensional structure. Bacillomycin D formed a monolayer film at the air-water interface and kept its turn conformation, as shown by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). To identify the membrane lipid target of bacillomycin D, its interactions with pure lipid monolayers were analyzed and an original behavior of the lipopeptide toward cholesterol-containing monolayers was shown. This original behavior was lost when bacillomycin D was interacting with pure cholesteryl acetate monolayers, suggesting the involvement of the alcohol group of cholesterol in the lipopeptide-cholesterol interaction. 相似文献
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Tuba Recber Gokcen Orgul Emine Aydın Atakan Tanacan Emirhan Nemutlu Sedef Kır Mehmet Sinan Beksac 《Biomedical chromatography : BMC》2020,34(8):e4842
The aim of this study was to demonstrate the altered metabolic infrastructure of pregnant women with methylenetetrahydrofolate reductase (MTHFR) polymorphisms at first trimester and during delivery. Eight singleton pregnant women with MTHFR polymorphisms were compared with 10 normal pregnant women. Maternal blood samples were obtained twice during their pregnancy period (between the 11th and 14th gestational weeks and during delivery). Metabolomic analysis was performed using GC–MS. The GC–MS based metabolomic profile helped identify 95 metabolites in the plasma samples. In the MTHFR group, the levels of 1-monohexadecanoylglycerol, pyrophosphate, benzoin, and linoleic acid significantly decreased (P ˂ 0.05 for all), whereas the levels of glyceric acid, l -tryptophan, l -alanine, l -proline, norvaline, l -threonine, and myo-inositol significantly increased (P ˂ 0.01 for the first two metabolites, P ˂ 0.05 for the others) at 11–14 gestational weeks. Conversely, the levels of benzoin, 1-monohexadecanoylglycerol, pyruvic acid, l -proline, phosphoric acid, epsilon-caprolactam, and pipecolic acid significantly decreased in the MTHFR group, whereas metabolites such as hexadecanoic acid and 2-hydroxybutyric acid increased significantly in the study group during delivery. An impaired energy metabolism pathway, vitamin B complex disorders, tendency for metabolic acidosis (oxidative stress), and the need for cell/tissue support seem prevalent in pregnancies with MTHFR polymorphisms. 相似文献
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