Temat: silica - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Radiation curing of silica for silica-rubber composites
Autorzy:: Dondi, D.
Palamini, C.
Pepori, F.
Buttafava, A.
Galinetto, P.
Faucitano, A.
Tematy:: radiation
silica-rubber composites
modified silica; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/148026.pdf Link otwiera się w nowym oknie
Opis:: The functional modification of silica samples based on the reaction of “grafting” of polybutadiene olygomers carried out by gamma-irradiation in the presence of air at room temperature has been investigated. The yield of grafted PB reaches a maximum at doses of about 30 kGy, then decreases as a consequence of the oxidative degradation. The reaction is accompanied by the build up of carbonyls and peroxides up to 0.1 moles/kg and it leads to a rapid consumption of the double bonds concentration as determined by both FTIR and Raman spectroscopy. The results of the EPR analysis are diagnostic of a mechanism of immobilization of the olygomer based on cross-linking of polybutadiene which is initiated by the SiO2 radiolytic species. Depending on the nature of the SiO2 species, the mechanism of initiation leads to immobilized PB either really grafted to the silica surface or simply physically absorbed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Collection of Industrial Oil Using Nanoparticles and Porous Powders of Silica
Autorzy:: Cho, Y.-S.
Moon, J.-W.
Tematy:: silica nanopowders
surface modification
porous silica
oil removal; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/351139.pdf Link otwiera się w nowym oknie
Opis:: Industrial oil was collected using hydrophobic silica powders. Silica nanopowder was modified with octadecyltriethoxysilane (OTS) using spray pyrolysis reactor continuously. Besides nanoparticles, mesoporous silica powder synthesized using Pluronic P104 was adopted as another oil adsorbents. Spherical macroporous or meso-macroporous silica particles were prepared by selfassembly for the removal of oil. The effects of the amount of powder on the oil adsorption were studied and compared with the results of various silica powders. The meso-macroporous silica particles were found to be the most efficient, indicating that both specific surface area and porosity played crucial role.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Titania/mesoporous silica nanotubes with efficient photocatalytic properties
Autorzy:: Cendrowski, K.
Tematy:: mesoporous silica nanotubes
silica-titania nanocomposite
photocatalysis
phenol decomposition; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/778607.pdf Link otwiera się w nowym oknie
Opis:: Ordered nanocrystalline titania-mesoporous silica nanotube structures are synthesized by hydrolysis of the titania precursor inside pours silica shell. Silica coating surrounding carbon nanotubes was further removed by thermal reduction. The proposed method of functionalization silica channels with the titania nanoparticles preclude aggregation of TiO₂ nanoparticles. The nanocrystalline silica/titania (mt-SiO₂ /TiO₂ ) nanotubes were prepared according to the describe method has high specific surface area and possesses excellent photocatalytic properties capable of decomposing phenol and methylene blue in a short time. Since the nanocrystalline TiO₂ is produced in the wall of the mesoporous silica tube, phenol or dye molecules can react with TiO₂ nanoparticles from both the inside and outside.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Oznaczanie krzemionki metodą chromatografii jonowej
Autorzy:: Łyko, A.
Michalski, R.
Tematy:: chromatografia jonowa
krzemionka
oznaczanie krzemionki
ion chromatography
silica
silica determination; Pokaż więcej
Wydawca:: Roble
Powiązania:: https://bibliotekanauki.pl/articles/274238.pdf Link otwiera się w nowym oknie
Opis:: Chromatografia jonowa to najważniejsza instrumentalna metoda oznaczania podstawowych jonów. W minionych latach dokonano ogromnego postępu związanego z jej zastosowaniem zdecydowanie wykraczającym poza standardowe analizy kationów i anionów w wodach i ściekach. Dotyczy to oznaczania różnych form jonowych tego samego pierwiastka, zjonizowanych substancji organicznych, a substancji które jeszcze do niedawna nie były w ogóle brane pod uwagę jako możliwe do oznaczania tą techniką analityczną, takich jak krzemionka. W pracy opisano metodę oznaczania SiO2 w próbkach o nieskomplikowanej matrycy jaką jest woda przeznaczona do spożycia oraz woda z jezior. Przedstawiono również parametry walidacyjne oraz badanie odzysku wzorca.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Lignosulfonate and silica as precursors of advanced composites
Autorzy:: Klapiszewski, Ł.
Nowacka, M.
Siwińska-Stefańska, K.
Jesionowski, T.
Tematy:: Magnesium lignosulfonate
silica
Silica/lignosulfonate composite
Physicochemical and structural properties; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/778432.pdf Link otwiera się w nowym oknie
Opis:: Advanced silica/lignosulfonate composites were obtained using magnesium lignosulfonate and silica precipitated in a polar medium. For comparative purposes analogous synthesis was performed using commercial silica Aerosil®200. Lignosulfonates are waste products of paper industry and their application in new multifunctional materials is of great economic interest. The composites obtained were subjected to thorough characterization by determination of their physicochemical, dispersive-morphological and electrokinetic properties. Their particle size distribution was measured, SEM images were taken, FT-IR analysis and colorimetric study were made, thermal and electrokinetic stabilities and parameters of porous structure were also determined. The results can be of interest in further application studies.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Application of sol-gel process for preparation of functional materials
Autorzy:: Gaishun, V. E.
Demidenko, O. M.
Kosenok, Y. A.
Kovalenko, D. L.
Semchenko, A. V.
Strek, W.
Tematy:: sol-gel
colored silica film
rust-proofing inorganic covers
colloidal nanosized silica; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Powiązania:: https://bibliotekanauki.pl/articles/385165.pdf Link otwiera się w nowym oknie
Opis:: A development of high-performance materials for electronics, optics, ceramics fabrication is restrained by traditional modes of their production. Basic technologies for materials include high-temperature physical and chemical processes and require special conditions to attain desired properties of final products. Advanced preparation methods for materials with new features are feasible on the basis of colloid-chemical processes and nanochemistry. In this respect the sol-to-gel transformation followed by solidification and chemical modification are of great interest to attain a variety of different functional properties of materials.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Silica-polymer composites as the novel antibiotic delivery systems for bone tissue infection
Autorzy:: Szewczyk, Adrian
Majda, Dorota
Górska, Monika
Konopacka, Agnieszka
Skwira, Adrianna
Sądej, Rafał
Prokopowicz, Magdalena
Opis:: Bone tissue inflammation, osteomyelitis, is commonly caused by bacterial invasion and requires prolonged antibiotic therapy for weeks or months. Thus, the aim of this study was to develop novel silica-polymer local bone antibiotic delivery systems characterized by a sustained release of ciprofloxacin (CIP) which remain active against Staphylococcus aureus for a few weeks, and do not have a toxic effect towards human osteoblasts. Four formulations composed of ethylcellulose (EC), polydimethylsiloxane (PDMS), freeze-dried CIP, and CIP-adsorbed mesoporous silica materials (MCM-41-CIP) were prepared via solvent-evaporation blending method. All obtained composites were characterized in terms of molecular structure, morphological, and structural properties by using Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX), and X-ray diffraction (XRD), thermal stability by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and in vitro antibiotic release. The antibacterial activity against Staphylococcus aureus (ATCC 6538) as well as the in vitro cytocompatibility to human osteoblasts of obtained composites were also examined. Physicochemical results confirmed the presence of particular components (FTIR), formation of continuous polymer phase onto the surface of freeze-dried CIP or MCM-41-CIP (SEM/EDX), and semi-crystalline (composites containing freeze-dried CIP) or amorphous (composites containing MCM-41-CIP) structure (XRD). TGA and DSC analysis indicated the high thermal stability of CIP adsorbed onto the MCM-41, and higher after MCM-41-CIP coating with polymer blend. The release study revealed the significant reduction in initial burst of CIP for the composites which contained MCM-41-CIP instead of freeze-dried CIP. These composites were also characterized by the 30-day activity against S. aureus and the highest cytocompatibility to human osteoblasts in vitro.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 8.

Tytuł:: New Material Nanocomposite Thermoplastic Elastomer with Low Cost Hybrid Filler Oil Palm Boiler Ash/Carbon Black
Autorzy:: Frida, Erna
Bukit, Nurdin
Sinuhaji, Perdinan
Bukit, Ferry Rahmat Astianta
Bukit, Bunga Fisikanta
Tematy:: waste
material
silica
compound; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/2202362.pdf Link otwiera się w nowym oknie
Opis:: This study aimed to prepare thermoplastic elastomeric nanocomposites with Low-Cost Hybrid Filler Oil Palm Boiler Ash/Carbon Black as New Material. Hybrid filler composites promise to overcome the limitations of composites. The effects offered by the matrix and filler are responsible for improving the properties of the composite. The preparation of thermoplastic elastomer was carried out in two stages. The first stage involves mixing a rubber compound with filler. The second stage is blending the compound, HDPE, and PE-g-MA using an Internal Mixer. The results show that the peak intensity increased along with the amount of OPBA in TPE. The increase in peak intensity was caused by the rise in the number of crystalline phases in the nanocomposite. In general, the absorption bands are almost the same. The samples analyzed showed absorption band vibrations (Si-O-Si), in-plane strain vibrations (Si-OH), and symmetric strain vibrations (Si-O-Si), C―H deformation, –CH symmetrical stretching of the CH2 group appeared on each sample that FTIR has analyzed. Thermoplastics show good interaction between filler and matrix, so it can be assumed that these interactions can improve the mechanical properties of TPE. Differential Scanning Calorimetry (DSC) shows an increase in the number of peaks in the sample with 60/40 phr filler.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Effect of SiO2 nanoparticles on drought resistance in hawthorn seedlings
Autorzy:: Struve, Daniel
Tomášková, Ivana
Ashkavand, Peyman
Zarafshar, Mehrdad
Tabari, Masoud
Wydawca:: Instytut Badawczy Leśnictwa (Forest Research Institute), Sekocin Stary, Poland
Opis:: Przemysław Szmit
Drought is a significant factor limiting crop production in arid regions while hawthorns (Crataegus sp.) are an important component of such region’s forests. Therefore, treatments that increase hawthorn drought resistance may also increase transplanting success. Thus, the physiological and biochemical responses of hawthorn seedlings to a factorial combination of different concentrations of silica nanoparticles (SNPs at 0, 10, 50 and 100 mg L-1) and three soil moisture treatments (without stress, moderate stress and severe stress) were investigated. Seedlings were irrigated with one of the four concentrations of SNPs for 45 days before exposing them to drought stress. Photosynthesis parameters, malondialdehyde (MDA), relative water content (RWC ), membrane electrolyte leakage (ELI) as well as chlorophyll, carotenoid, carbohydrate and proline content were determined. At the end of the experiment, positive effects by SNP pre-treatment on physiological indexes were observed during drought stress. Under drought conditions, the effect of SNPs on photosynthetic rate and stomatal conductance was evident. Although the SNPs increased plant biomass, xylem water potential and MDA content, especially under drought conditions, RWC and ELI were not affected by the SNP pre-treatments. Seedlings pre-treated with SNPs had a decreased carbohydrate and proline content under all water regimes, but especially so under drought. Total chlorophyll content and carotenoid content did not change among the treatments. Generally, the findings imply that SNPs play a positive role in maintaining critical physiological and biochemical functions in hawthorn seedlings under drought stress conditions. However, more studies are needed before the physiological and biochemical basis of induced drought resistance can be determined.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 10.

Tytuł:: Application of modified silica gel in the process of trypsin immobilization
Autorzy:: Miłek, Justyna
Kwiatkowska-Marks, Sylwia
Trawczyńska, Ilona
Tematy:: trypsin
immobilization
silica gel
biocatalyst; Pokaż więcej
Wydawca:: Uniwersytet Warmińsko-Mazurski w Olsztynie
Powiązania:: https://bibliotekanauki.pl/articles/297914.pdf Link otwiera się w nowym oknie
Opis:: The paper presents the use of modified silica gel for the production of immobilized trypsin from bovine pancreas. Silica gel was modified with 3-aminopropyltriethoxysilane, followed by glutaraldehyde. The influence of stirring time on activity of the prepared biocatalyst was determined for individual stages of the modification. Activity of both native and immobilized trypsin was measured using Kunitz method. At the temperature of 55℃ and pH 7.6 native and immobilized trypsin onto modified silica gel indicate optimum activity. The influence of multiple recycling and storage time on activity of immobilized trypsin was tested. After fourteen days of storage at the temperature of 4℃ immobilized trypsin exhibits 75% of its initial activity.
Dostawca treści:: Biblioteka Nauki

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