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1.
Polymers (Basel) ; 15(15)2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37571100

RESUMO

A new para-aramid aerogel based on a polymer made by the reaction of terephthaloyl dichloride with 2-(4-aminophenyl)-1H-benzimidazol-5-amine (PABI) is introduced. The aerogel readily bound Pd (+2) ions and was used as a hydrogenation catalyst in some industrially actual reactions. The new material, which did not contain p-phenylenediamine moieties, was prepared in two form factors: bulk samples and spherical pellets of 700-900 µm in diameter. Aerogels were synthesized from 1% or 5% solutions of PABI in N,N-dimethylacetamide via gelation with acetone or isopropanol and had a density of 0.057 or 0.375 g/cm3 depending on the concentration of the starting PABI solution. The specific surface area of the obtained samples was 470 or 320 m2/g. Spherical pellets containing Pd were prepared from a solution of PdCl2 in PABI and were used as heterogeneous catalysts for the gas-phase hydrogenation of unsaturated organic compounds presenting the main types of industrially important substrates: olefins, acetylenes, aromatics, carbonyls, and nitriles. Catalytic hydrogenation of gaseous hexene-1, hexyne-3, cyclohexene, and acrylonitrile C=C bond proceeded with a 99% conversion at ambient pressure, but the catalyst failed to reduce acetone at 150 °C and benzene and ethyl acetate even at 200 °C. The only product of acrylonitrile hydrogenation was propionitrile. The prepared catalysts showed high selectivity, which is important for the chemistry of complex organic compounds.

2.
Nanomaterials (Basel) ; 12(22)2022 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-36432319

RESUMO

The aim of the study is to investigate the influence of the solvents applied both in sol-gel process and for supercritical drying (SCD) on NiO aerogels' properties. NiO aerogels were synthesized using methanol and 2-methoxy-ethanol (MeGl) as sol solvents. SCD was performed using iso-propanol, methanol and tert-butyl-methyl ether as supercritical fluids. The obtained samples were characterized using low-temperature nitrogen adsorption, X-ray diffraction analysis, mass-spectra analysis and STEM and TEM methods. It was found that specific surface area and the phase and chemical composition strongly depend on the synthesis conditions. We revealed that Ni2+ cations were reduced into Ni0 when 2-methoxy-ethanol was applied as a sol solvent. The mechanism of the Ni2+ cations reduction is proposed. We consider that at the stage of sol preparation, the Ni2+-MeGl chelate was formed. This chelate decomposes at the SCD stage with the release of MeGl, which, in turn, eliminates methanol and leads to the formation of aldehyde. The latter is responsible for the nickel reduction. The proposed mechanism was confirmed experimentally.

3.
Molecules ; 27(7)2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35408484

RESUMO

Cell culturing methods in its classical 2D approach have limitations associated with altered cell morphology, gene expression patterns, migration, cell cycle and proliferation. Moreover, high throughput drug screening is mainly performed on 2D cell cultures which are physiologically far from proper cell functions resulting in inadequate hit-compounds which subsequently fail. A shift to 3D culturing protocols could solve issues with altered cell biochemistry and signaling which would lead to a proper recapitulation of physiological conditions in test systems. Here, we examined porous ultra-high molecular weight polyethylene (UHMWPE) as an inexpensive and robust material with varying pore sizes for cell culturing. We tested and developed culturing protocols for immortalized human neuroblastoma and primary mice hippocampal cells which resulted in high rate of cell penetration within one week of cultivation. UHMWPE was additionally functionalized with gelatin, poly-L-lysine, BSA and chitosan, resulting in increased cell penetrations of the material. We have also successfully traced GFP-tagged cells which were grown on a UHMWPE sample after one week from implantation into mice brain. Our findings highlight the importance of UHMWPE use as a 3D matrix and show new possibilities arising from the use of cheap and chemically homogeneous material for studying various types of cell-surface interactions further improving cell adhesion, viability and biocompatibility.


Assuntos
Técnicas de Cultura de Células , Polietilenos , Animais , Técnicas de Cultura de Células/métodos , Células Cultivadas , Camundongos , Peso Molecular , Polietileno/química , Polietilenos/química , Porosidade
4.
Ultrason Sonochem ; 60: 104788, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31550644

RESUMO

To prevent possible spread of nosocomial infections - HAI (Healthcare Acquired Infections) in healthcare facilities, Antibacterial textiles are developed. This carried out study has been conducted to assess the feasibility of the method of obtaining antibacterial coatings on textile materials. Specifically, the sol-gel method for synthesis of titanium dioxide nanoparticles in combination with zinc oxide nanoparticles from titanyl sulphate and zinc nitrate hexahydrate has been investigated. During the synthesis of titanium dioxide nanoparticles in combination with the zinc oxide nanoparticles, the coated textile material showed stable antibacterial properties with a suppression level ofEscherichia coliof more than 99.99%. The method has been tested on a semi-industrial scale in roll-to-roll experimentby applying homogenous coatings at a speed of 1,5 m per minute.

5.
Molecules ; 24(21)2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31731434

RESUMO

A series of carbon aerogels (C-AGs) were prepared by the pyrolysis of resorcinol-formaldehyde aerogels at 700-1100 °C as potential supercapacitor electrodes, and their texture and electrochemical properties were determined. The specific surface area of all C-AGs was in the range of 700-760 m2/g, their electron conductivity increased linearly from 0.4 to 4.46 S/cm with an increase of the pyrolysis temperature. The specific capacitance of electrode material based on C-AGs reached 100 F/g in sulfuric acid and could be realized at a 2 A/g charge-discharge current, which makes it possible to use carbon aerogels as electrode materials.


Assuntos
Carbono/química , Formaldeído/química , Géis/química , Resorcinóis/química , Capacitância Elétrica , Condutividade Elétrica , Eletroquímica , Eletrodos , Géis/síntese química , Nitrogênio/química , Temperatura
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