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1

Thermal properties of porous sodium polyacrylate/silica nanocomposites

Korobeinyk Alina, Yurchenko Gabriella, Matkovsky Alexander, Tertykh Valentin

Polimery

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2023

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Vol. 68, nr 2

106--112

EN

Porous sodium polyacrylate/silica (SPA/SiO2) nanocomposites were obtained in a single-stage sol-gel process involving the acidic hydrolysis of tetramethoxysilane (TMOS) in the presence of SPA. The TMOS/SPA molar ratio ranged from 2:1 to 8:1. The physical and thermal properties of the nanocomposites were characterized by FTIR, SEM, TGA and adsorption analysis (BET, BJH). The mechanical and chemical treatment of the composite after the synthesis increased its specific surface area without significantly changing thermal properties. The process enables pore size control.

PL

Porowate nanokompozyty poliakrylan sodu/krzemionka (SPA/SiO2) otrzymano w jednoetapowym procesie zol-żel polegającym na kwaśnej hydrolizie tetrametoksysilanu (TMOS) w obecności SPA. Stosunek molowy TMOS/SPA wynosił od 2:1 do 8:1. Właściwości fizyczne i termiczne otrzymanych nanokompozytów scharakteryzowano za pomocą FTIR, SEM, TGA i analizy adsorpcyjnej (BET, BJH). Mechaniczna i chemiczna obróbka kompozytu po procesie syntezy zwiększyła jego powierzchnię właściwą bez znaczącej zmiany właściwości termicznych. Proces umożliwia kontrolę wielkości porów.

2

NiTiO3/MnFe2O4 ferrite composites: synthesis, optical, ferroelectric and magnetic properties

Thom Dang Thi, Tuan Nguyen Hoang, Ngoc Tran Vu Diem, Nga Nguyen Tuyet, Phuong Nguyen Thanh, Dung Dang Duc, Thoa Do Thi Kim, Bac Luong Huu

Materials Science Poland

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2022

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Vol. 40, No. 4

43--53

EN

This work reported the successful synthesis of ilmenite-spinel (1 − x)NiTiO3-xMnFe2O4 (x = 0, 0.05 and 0.10) composites by a simple sol-gel method. Phase formation of composites was analyzed by the X-ray diffraction method. All the synthesized samples formed diphasic ilmenite-ferrite composites without any trace of impurity or intermediate phase. The optical properties of synthesized composites were characterized by diffuse reflectance UV–visible spectroscopy. MnFe2O4 phase modified the optical band gap of NiTiO3 material and shifted its optical bandgap value toward lower energy. Ferroelectric and magnetic hysteresis loops were investigated at room temperature. The hysteresis loops indicated the typical ferromagnetic and ferroelectric nature of all composites at room temperature. In P-E loops, the remanent polarization (Pr) and saturation polarization (Ps) showed a slight increase in the sample with 5% MnFe2O4 phase addition. However, the lossy P-E loop was observed in the sample with the addition of 10% MnFe2O4. The presence of ferrite MnFe2O4 phase in NiTiO3 material enhanced the magnetic properties of NiTiO3 at room temperature. The M-H loops of NiTiO3-MnFe2O4 composites presented a ferromagnetic behavior with a dramatic increase in saturation magnetization with an increase of ferrite phase addition.

3

Bio-dielectric based on superconductors yttrium calcium barium copper oxide (YCaBa2Cu3O7−x) from eggshell as calcium oxide source via sol-gel process

Toumvong Wipawadee, Chitcharoentaweechoke Pornnita, Tangboriboon Nuchnapa

Materials Science Poland

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2021

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Vol. 39, No. 3

305--318

EN

Eggshell is a rich source of calcium that is a dielectric material used for doping in a superconductor. Yttrium calcium barium copper oxide (YxCa1−xBa2Cu3O7) was prepared using the sol-gel process and fired at 900 °C or 1,000 °C. The stoichiometric ratio of the raw materials Y2O3:BaCl2:CuO:CaO was 1:2:3:1 based on the molar mass. The obtained YCaBCO had an orthorhombic crystal structure composed of distorted oxygen-deficient perovskite. The orthorhombic structure was unsymmetrical, providing a substantial increase in the physical electromagnetic properties of the superconductor. The YBCO-900-reference analyzed using an impedance analyzer in the range from 500 Hz to (1 × 106) Hz and at room temperature (27 °C) had the following values for capacitance, electrical conductivity, and dielectric constant ± standard error: 8,286.70 ± 28.49 pF, (3.60 ± 0.01) × 107 S/m, and 1,874.794 ± 6.446, respectively. The YCaBCO-900-eggshell (YxCa1−xBa2Cu3O7) analyzed at 500 Hz at room temperature (27 °C) had high values for capacitance, electrical conductivity, and dielectric constant, namely, 8,540.10 ± 2.00 pF, (1.32 ± 0.00) × 108 S/m, and 1,988.540 ± 0.500, respectively. Furthermore, the YCaBCO-900-eggshell had electrical properties (capacitance, conductivity, and dielectric constant values) higher than those of YCaBCO-900-commercial grade measured under the same conditions. The YCaBCO-900-com grade had capacitance of 8,225.75 ± 0.73 pF, electrical conductivity of (1.40 ± 0.01) × 108 S/m, and dielectric constant of 1,874.59 ± 0.17, respectively. Therefore, eggshell is an alternative dielectric material useful for doping in yttrium barium copper oxide (YBCO) to form YCaBCO, thus causing an increase in its electrical properties. The obtained superconductor is a candidate that could be applied in many industries.

4

Study on Magnetic Properties of the U-Type Ferrite According to Substituted Elements

Jeong Kwang-Pil, Kim Jeong-Gon, Yang Su-Won, Yun Jae-Ho, Choi Jin-Hyuk

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 2

501--505

EN

The magnetic properties of the U-type ferrite synthesized by a sol-gel process had studied by substituting cobalt with manganese or zinc in cobalt-based U-type ferrite. The substituted U-type ferrite showed a dominant crystal structure at a different substitution ratio of manganese and zinc. The change of the starting temperature of U-type ferrite formation according to substitutional elements was confirmed by TG-DTA analysis. In the case of manganese substitution, the starting temperature of U-type ferrite formation lowered, and on the contrary, when zinc was substituted, it became higher. The magnetic properties of the U-type ferrite substituted with manganese showed a tendency that the saturation magnetization was decreased and the coercivity was increased as the manganese ratio increased. The highest saturation magnetization was 57.9 emu/g in the specific composition (Ba4Co0.5Zn1.5Fe36O60) substituted with zinc.

5

Electrical transport and magnetoresistance of double layered CMR manganites R1.2Sr1.8Mn2O7(R = La, Pr, Sm)

Reddy Y. S.

Materials Science Poland

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2017

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Vol. 35, No. 2

440--446

EN

Polycrystalline bulk samples of double layered (DL) colossal magnetoresistive (CMR) manganites R1.2Sr1.8Mn2O7 (R = La, Pr, Sm) were prepared by sol-gel method to study the effect of size of lanthanide ion on their magnetotransport properties. The electrical resistivity of the samples was investigated in the temperature range of 70 K to 300 K at different magnetic fields. The samples LSMO and PSMO show insulator-to-metal transition (IMT) behavior, while SSMO sample exhibits insulating behavior in the entire temperature range with a very large value of resistivity. The insulator-to-metal transition temperature (TIM) decreases from 123 K (LSMO) to 90 K (PSMO) and disappears in SSMO sample. To explain the electrical transport above TIM, the temperature dependent resistivity data (T > TIM) of all the samples were fitted to the equations of different conduction models. The results indicate that the conduction at T > TIM is due to Mott variable range hopping (VRH) mechanism in the LSMO and PSMO samples, while Efros-Shkloskii (ES) type of VRH model dominates the conduction process in the SSMO sample. All the three samples show increasing magnetoresistance (MR) even below TIM and the maximum MR is shown by LSMO (39 % at 75 K, 3 T).

6

Synthesis and characterization of nanocrystalline barium strontium titanate powder by a modified sol-gel processing

Araghi A. M. E., Shaban N., Bahar M.

Materials Science Poland

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2016

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Vol. 34, No. 1

63--68

EN

In this research work, nanocrystalline BST (Ba0.6Sr0.4 TiO3) powders were synthesized through a modified sol-gel process, using barium acetate, strontium acetate and titanium isopropoxide as the precursors. In this process, stoichiometric proportions of barium acetate and strontium acetate were dissolved in acetic acid and titanium (IV) isopropoxide was added to form BST gel. The as-formed gel was dried at 200 °C and then calcined in the temperature range of 600 to 850 °C for crystallization. The samples were characterized by infrared spectroscopy method (FT-IR), X-ray diffraction technique (XRD) and field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy. EDS analysis of these samples confirmed the formation of the final phase with the special stoichiometry. The formation of a cubic perovskite crystalline phase with nanoscale dimension was detected using the mentioned techniques. The results showed that the obtained crystallite sizes were 33 and 37 nm for BST powder calcined at 750 and 850 °C, respectively.

7

ZrO2-CeO2 ceramic powders obtained from a sol-gel process using acetylacetone as a chelating agent for potential application in prosthetic dentistry

Nakonieczny D., Paszenda Z., Drewniak S., Radko T., Lis M.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 3

53--60

EN

Purpose: The main objective of this study was to obtain single-phase β-ZrO2 powders with so-called soft agglomerates reproducibile morphology with acetyl-acetone as a chelating-agent. To the best of our knowledge there is no avaiable data which determine the effect of acetyl acetone on the phase composition and morphology of ceria-doped ZrO2 powders for biomedical applications. Methods: Twenty variants of powders with different water to zirconia precursor and acetylacetone to zirconia precursor molar ratios were prepared. 0.9ZrO20.1CeO2 powders were obtained by a hydrolysis and condensation and further calcination of zirconium n-propoxide in a simple one-step sol-gel process. Influence of acetyloacetone to zirconia precursor on the phase composition ratio and water to zirconia precursor was investigated. Samples have been characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), thermal analysis (TGA/DTA) and scanning electron microscopy (SEM) measurements. Results: Ceramic powders prepared by sol-gel process, according to the various concentration of chelating agent and water show different morphology and phase composition. Conclusions: Higher molar ratios of AcAc in range with smaller amounts of water cause hard agglomerates, obtained powders are characterized by highly thermally stable behaviour and various phase composition. With higher molar ratios of water to zirconium-n-propoxide so-called soft agglomerates and one phase powders are obtained.

8

Wpływ modyfikacji wstępnej obróbki powierzchniowej stopu AA2024-T3 na właściwości ochronne powłoki organicznej

Kapuścińska A., Kwiatkowski L.

Inżynieria Powierzchni

|

2015

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nr 2

41--46

PL

Celem pracy było opracowanie metody wstępnej obróbki powierzchniowej stopu AA2024-T3 i zbadanie jej wpływu na właściwości ochronne powłoki organicznej w porównaniu z powłoką naniesioną na podłoże chromianowane. Zasadniczym procesem przygotowania powierzchni było fosforanowanie amorficzne. Etap doszczelnienia uzyskanej w tym procesie powłoki fosforanowo-tlenkowej przeprowadzono metodą chemiczną w wodnym roztworze krzemianu sodu z dodatkiem inhibitora 2-merkaptobenzoksazoł (MBX, wariant I) oraz w procesie zol-żel z prekursorów tetrametoksysilan (TMOS)/dietoksydimetylosilan (DEDMS) z wprowadzonym do mieszaniny inhibitorem MBX (wariant II). Odporność korozyjną wytworzonych powłok konwersyjnych pokrytych powłoką organiczną oceniono za pomocą elektrochemicznej spektroskopii impedancyjnej EIS. Mimo tego że pierwsza metoda doszczelnienia jest znacznie wygodniejsza w aplikacji oraz mniej kosztowna, to nie zapewnia odporności korozyjnej porównywalnej z powłoką hybrydową TMOS/DEDMS. Widma impedancyjne zarejestrowane dla wariantu doszczelnienia powłoki fosforanowanej w procesie zol-żel z MBX w początkowej fazie ekspozycji w roztworze 0,5 MNa2SO4 + 0,01M NaCl o pH =6,0 wskazują na porównywalne z powloką chromianową właściwości ochronne. Po 168 godzinach ekspozycji pojawienie się drugiej stałej czasowej dla systemu ochronnego z powloką hybrydową, świadczy o pogorszeniu właściwości barierowych, podczas gdy dla powłoki organicznej na podłożu chromianowanym przebieg widm nie uległ zmianie podczas pełnego cyklu badań.

EN

The study was aiming at the development of surface pre-treatment of AA2024-T3 alloy prior to organic coating as the alternative to chromating. The main conversion coating was obtained by means of amorphous phosphating followed by two types of sealing process. The process of sealing was carried out in an agueous solution of sodium silicate with the addition of 2 mercaplobenzoxazole (MBX, version I) and in sol-gel process using precursors TMOS/DEDMS which were successfully used in another work for Mg surfaces. This mixture was doped with MBX and performed as version II. The corrosion resistance of amorphous phosphate coating with or without sealing and top coated by organic coating was evaluated using Electrochemical Impedance Spectroscopy (EIS). While an application of the first method is much more robust and less expensive, it does not provide comparable corrosion resistance with the hybrid inorganic-organic layer formed in soil gel process. For the latter, the impedance spectra obtained at the initial stage of exposition in 0,5 M Na2SO4 + 0,01 M NaCl solution showed a similar course to chromate conversion coating, however, unlikely to chromate containing coating system, after a longer time (168 h) an occurrence of a time constant in lower frequencies range indicated an onset of corrosion process.

9

Luminescent homo- and hetero-metallic hybrid molecular materials constructed by covalent grafting

Wang F. F., Yan B.

Materials Science Poland

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2013

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Vol. 31, No. 1

108-114

EN

In this paper, 3-(triethoxysilyl)-propyl isocyanate (abbreviated as TESPIC) was modified by ethylparaben (EPB) to produce corresponding organic-inorganic monomers (EPB-TESPIC) with two components equipped with covalent bonds, which not only can coordinate to RE ions (Tb3+ and Eu3+) but also act as a sol-gel precursor. Luminescent hybrid materials consisting of terbium-europium complex, covalently bonded to silica-based network, have been obtained in situ via a sol-gel approach. Proton nuclear magnetic resonance spectroscopy (1HNMR) and Fourier transform infrared spectroscopy (FT-IR) were applied to characterize the structure of EPB-TESPIC. UV-visible, phosphorescence, and luminescence spectra were obtained to characterize the photophysical properties of the obtained hybrid material. Through co-hydrolysis and polycondensation, Tb3+ and Eu3+ can be introduced into the same organic-inorganic hybrid monomer, forming Si-O backbones. The experimental results show that the strong luminescence of rare-earth ions substantiates the optimum energy match and effective intramolecular energy transfer between the triplet state energy of coordination complex and the emissive energy level of the rare-earth ions. The hybrid material systems are expected to have potential applications in photophysical sensors.

10

Photofunctional terbium centered inorganic/organic hybrid material with the functionalized 5-dihydroxybenzoate linkage

Li Y., Sui Y. L., Yan B.

Materials Science Poland

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2012

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Vol. 30, No. 1

39--44

EN

In this study, silica-based organic-inorganic hybrids were prepared using sol-gel methods. A new kind of monomer (DHBA-TESPI) was derived by modifying the double hydroxyl groups of 3, 5-dihydroxybenzoic acid (DHBA) with 3-(triethoxysilyl)-propyl isocyanate (TESPI) through the addition reaction. Then, the obtained compound and tetraethoxysilane (TEOS) were used as the inorganic and organic counterparts respectively. Coordination reaction between Tb3+ and the carboxylic groups of the monomer happen simultaneously. IR, NMR, UV/Vis absorption, low-temperature phosphorescence spectroscopy and fluorescence spectroscopy were used to characterize the hybrids. The final materials exhibited strong green-colored fluorescence (Tb3+), which can be explained by the intramolecular energy transfer caused by coordination of the organic counterpart. The spectroscopic data also revealed that the triplet state energy of the organic ligand matches the emissive energy level of Tb3+.

11

Synthesis of organic-inorganic hybrids based on cellulose acetate butyrate

Wojciechowska P.

Polimery

|

2009

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T. 54, nr 11-12

845-848

EN

Novel organic-inorganic hybrids based on cellulose acetate butyrate (CAB) were synthesized applying sol-gel process. The inorganic phase was introduced into polymer matrix by hydrolysis and condensation using tetraethoxysilane (TEOS) as the precursor, under acidic conditions. The obtained organic-inorganic hybrids were characterized by different techniques such as IR spectroscopy, thermogravimetric analysis (TGA), solid state 29Si NMR and scanning electron microscopy (SEM). Organic-inorganic hybrids obtained with 20% of diethyl phthalate (DEP) as plasticizer exhibit good transparency in comparison with unmodified CAB.

PL

Nowe organiczno-nieorganiczne materiały hybrydowe na bazie octanomaślanu celulozy (CAB) otrzymano techniką zol-żel. Fazę nieorganiczną wprowadzano do matrycy polimeru w wyniku reakcji hydrolizy w środowisku kwaśnym i kondensacji stosując jako prekursor tetraetoksysilan (TEOS). Otrzymane materiały charakteryzowano za pomocą spektroskopii w podczerwieni (IR), analizy termograwimetrycznej (TGA), magnetycznego rezonansu jądrowego ciał stałych 29Si NMR oraz skaningowej mikroskopii elektronowej (SEM). Organiczno-nieorganiczne hybrydy otrzymane z udziałem 20% ftalanu dietylu jako plastyfikatora cechują się dobrą przejrzystością w porównaniu z polimerem niemodyfikowanym.

12

Nanonapełniacze kompozytów polimerowych. Część II. Krzemionka

Malesa M.

Elastomery

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2006

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T. 10, nr 2

10-15

PL

Kompozyty polimerowe zawierające nanonapełniacze charakteryzują Ą dużo lepszymi właściwościami wytrzymałościowymi niż kompozyty zawierająu napełniacze tradycyjne. Wynika to z możliwości uzyskania lepszej dyspersji nanocząstek w matrycy polimerowej. Obecnie obserwuje się bardzo duże zainteresowanie naukowców opracowywaniem efektywnych sposobów otrzymywania i badaniem właściwości nanokompozytów typu polimer-nanonapełniaa W artykule przedstawiono informacje na temat krzemionki o rozmiarach rzęds manometrów, metod wprowadzania tego typu napelniacza do polimeru orą właściwości tak otrzymanych kompozytów. Dokonano przeglądu dostępnym w tym zakresie doniesień literaturowych.

EN

Polymer nanocomposites containing nanofillers are characterized by much better strength properties than composites containing conventional fillers. One of the reasons for this is possibility of obtaining nanoparticle better dispersion in polymer matrix. There is current great interest of researchers in investigation in development efficient methods of preparation and properties of nanocomposites polymer-nanofiller type. In this paper informations concerning of silica (nano size particles), introducing to the polymer and properties obtained composites are presented. A review of literature date in this range was done.

13

Octasilsesquioxanes as Hybrid Nanocomposite Platforms. II. Synthesis, Characterization and Properties of Some Alkyl-functionalized Sislesquioxanes

Dare E., Olatunji G., Ogunniyi D.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 1

101-107

EN

The syntheses of octaalkylsilsesquioxanes 3, 4, 5 and 6 have been achieved by the platinum- catalyzed hydrosilylation of octahydrogensilsesquioxane 2 with _-halo-alkenes and other unsaturated substrates. These compounds were characterized by spectroscopic techniques and elemental analysis. Thermogravimetric analyses of 3 and 4 shows that they are reasonably stable thermally, and may act as building blocks to ceramics, nanometer ball bearing at around 400°C and photoresist materials.

14

Textural properties of silica-based organic-inorganic polymer hybrid xerogels

Zaręba-Grodź I., Miśta W., Sikora A., Gotszalk T., Stręk W., Hermanowicz K., Maruszewski K.

Materials Science Poland

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2005

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Vol. 23, No. 1

147--158

EN

Samples of xerogels containing organic polymers were prepared by the sol-gel method via the reaction of tetraethoxysilane (TEOS) and organic monomers with an acidic catalyst. These materials were obtained as transparent and homogeneous bulk materials. The samples were characterized by Raman and IR spectroscopies, N2-adsorption (77 K), and atomic force microscopy (AFM). Specific surface areas and porosities of the samples were estimated from nitrogen adsorption-desorption isotherms at 77 K. Textural properties such as specific surface areas (SBET), pore volume (Vp), average pore sizes (Rp), and micropore volume (VDR) were obtained. The complete adsorption-desorption isotherms and pore size distributions were analysed following the Dollimore-Heal method. Atomic force microscopy was used to investigate the morphology and roughness of the samples.

15

Struktura powłok SiO2 oraz SiO2-TiO2 wytwarzanych metodą zol-żel

Walczak M., Bieniaś J.

Eksploatacja i Niezawodność

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2004

|

nr 2

64-68

PL

W pracy przedstawiono rezultaty badań powłok przejściowych krzemionkowych i krzemionkowa - tytanowych na czystym technicznie tytanie oraz jego stopie Ti6Al4VELI. Powłoki SiO2 i SiO2-TiO2 byty nanoszone na tytanowe podłoże metodą zol-żel. Do badania składu i morfologii warstwy ceramicznej użyto mikroskopii skaningowej i analizy chemicznej EDX. Na podstawie przeprowadzonych badań oraz analizy studiów literatury można stwierdzić, że powłoki zol-żel wykazują dobre połączenie z materiałem podłoża, są jednorodne chemicznie i charakteryzują się stosunkowo dużą chropowatością.

EN

Results of a study of silica and silica-titania coatings for the creation of intermediate interfaces between commercially-pure Ti or titanium alloy Ti6Al4VELI are presented. Coatings ofSiO2 and SiO2-TiO2 on base titanium were deposited using sol-gel method. Surface morphology and chemical compositions of the coatings were studied by using scanning electron microscopy with electron diffraction spectroscopy. It is found that: coatings obtained by the sol-gel method are compact, chemically homogeneous and relatively rough.

16

Rola wody, EBH i temperatury w preparatyce hybrydowych powłok otrzymywanych za pomocą metody zol-żel.

Głuszek J., Masalski J., Kucharczyk B., Golubski Z.

Inżynieria Materiałowa

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2002

|

R. XXIII, nr 5

355-358

PL

Za pomocą metody zol-żel wytworzono na stali chirurgicznej typu 316L powłoki nieorganiczno-organiczne wykorzystując tetraetoksysilan (TEOS) i eter bisglicydowy hydrochinonu (EBH). Wielowarstwowe powłoki otrzymywano metodą zanurzeniową z zoli zawierających różne ilości TEOS-u, wody, alkoholu etylowego i EBH. Stosowano dwie różne temperatury wypalania powłok. Dokonano elektrochemicznej oceny właściwości ochronnych powłok w roztworze Ringera za pomocą metody stałoprądowej. W oparciu o chrakterystyki polaryzacyjne dokonano oceny jakości powłok. Posłużono się arbitralnie wybranymi wielkościami i -750mv, E2mi A. Wyłoniono siedem najlepszych powłok i uszeregowano je (ranking) biorąc pod uwagę dodatkowy, trzeci parametr opór polaryzacyjny. W preparatyce zoli najbardziej odpowiednim stosunkiem molowym prekursora TEOS do wody jest stosunek 1:5. Właściwości ochronne powłok wypalanych w temperaturze 300 stopni Celsjusza przewyższają właściwości ochronne powłok wypalanych w temperaturze 250 stopni Celsjusza. Nie można jednoznacznie określić, jaki jest wpływ EBH zawartego w zolu na odporność korozyjną powłok (zbyt mała rozpuszczalność EBH w zolu). Małe zmiany w preparatyce często wywierają nieproporcjonalnie duży wpływ na jakość powłoki.

EN

The inorganic-organic coatings on the surgical 316L stainless steel have been synthesized by sol-gel techniques from TEOS and EBH. The multilayer dip coatings have been prepared from sols with different molar ratios of TEOS, water, ethanol and EBH. Coatings have been heated at two different temperatures. The electrochemical estimation by d.c. (direct connect) measurements of protective coatings in Ringer's solution is reported. Coatings performance has been compared using polarization characteristics. Two arbitrary chosen values were applied: i-750mv and E2mu A. The best seven coatings were selected and ranked with regard to the additional parameter - the polarization resistance. In preparation of sols the most appropriate molar TEOS - water ratio was 1:5. Heat treatment at 300 degrees centigrade lead to more remarkable improvements in corrosion resistance of coatings than that at 250 degrees centigrade. It is impossible to univocally determine the effect of EBH content in sol on corrosion resistance of coatings (poor dissolution of EBH in sol). Small changes in the preparation process can often have disproportionate effect on the quality of coating.

17

Rola nanokrzemionki w preparatyce powłok SiO2 otrzymywanych metodą zol-żel.

Chęcmanowski J.G., Głuszek J., Masalski J., Krysztafkiewicz A.

Inżynieria Materiałowa

|

2002

|

R. XXIII, nr 5

359-363

PL

Otrzymano powłoki ochronne SiO2 na stali chirurgicznej typu 316L wykorzystując metodę zol-żel. Wielowarstwowe powłoki otrzymano metodą zanurzeniową z zoli, w których prekursorem był tzw. TEOS (tetraetoksysilan), a także alkohol etylowy, kwas azotowy i kwas octowy w odpowiednim stosunku molowym. Następnie do zoli dodawano różne ilości nanokrzemionki w obecności dwóch wybranych surfaktantów SDS (dodecylosiarczan sodowy) oraz DODAB (bromek diodecylodimetyloamoniowy). Określono wpływ temperatury wypalania powłok na właściwości ochronne stali w roztworze Ringera. Dokonano elektrochemicznej oceny właściwości ochronnych powłok, wykorzystując metodę stałopradową. W oparciu o charakterystyki polaryzacyjne dokonano oceny jakości powłok, wykorzystując dwie arbitralnie wybrane wielkości i 750mV i E 2muA. Ponadto wyznaczono trzeci parametr Rp - opór polaryzacyjny. Wpływ dodatku nanokrzemionki jest korzystny na właściwości ochronne powłok.

EN

The SiO2 protective coatings on surgical 316L stainless steel were prepared by sol-gel method. The multilayer coatings were deposited by dip method using sols containing appropriate molar ratios of precursor TEOS, ethanol, nitric acid and acetic acid. Different amounts of nanosilica with two chosen surfactants: SDS (sodium dodecylsulphate) and DODAB (didodecyldimethylammonium bromide) were added to the applied sols. The effects of curing temperature on protective properties of coatings in Ringer's solution were determined. The electrochemical evalution of coatings using d.c. measurements were reported. Coatings performance has been compared using polarisation characteristics by employing two arbitrary chosen quantities: i -750mV and E2 muA. Furthermore the third parameter Rp - polarisation resistance, was determined. The positive effect of nanosilica on protective properties of coatings was determined.

18

Porównanie spiekania ceramiki konwencjonalnej i nanostrukturalnej.

Rzeszotarska J., Ranachowski J.

Szkło i Ceramika

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2000

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R. 51, nr 3

7-13

19

Synthesis of oxide-supported vanadium catalysts and their activity in ethylene polymerization

Czaja K., Korach Ł., Białek M.

Polimery

|

1999

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T. 44, nr 6

426-429

EN

The activity of oxide-supported vanadium-based catalyst systems (VOCl3/Et2AlCl) in low-pressure ethylene polymerization and the properties of the resulting polyethylenes were studied in relation to the type and mode of modification of the oxide support. Alumina, silica and an unconventional silica-type material prepared by the sol-gel process were used as supports. Results are compared with those obtained earlier with a catalyst supported on MgCl2(THF)2. Of the oxides studied, the silica-type sol-gel material dehydrated and subsequently modified with Et2AlCl proved to be the best carrier for a vanadium catalyst. The polyethylene prepared by using this catalyst support was found to exhibit good morphology, especially as compared with the polymer prepared over the more active Mg-V-Al catalyst.

PL

Zbadano aktywność katalityczną układu wanadowego (VOCl3/AIEt2Cl) w procesie niskociśnieniowej polimeryzacji etylenu oraz właściwości otrzymanego polietylenu w zależności od rodzaju nośnika tlenkowego i sposobu jego modyfikacji (temperatura prażenia, modyfikacja chemiczna związkiem aloorganicznym). Jako nośniki stosowano typowe żele Al2O3 lub SiO2 oraz nowy, niekonwencjonalny nośnik krzemionkowy sporządzony na drodze syntezy typu zol-żel. Otrzymane wyniki porównano z danymi uzyskanymi wcześniej z zastosowaniem katalizatora naniesionego na MgCl2(THF)2. Spośród wszystkich badanych tlenków najlepszym nośnikiem katalizatora wanadowego okazał się zolowo-żelowy proszek krzemionkowy wstępnie odwodniony i następnie modyfikowany AlEt2Cl. Polietylen otrzymany przy użyciu tego katalizatora odznaczał się dobrą morfologią, zwłaszcza w porównaniu z polimerem otrzymanym wobec aktywniejszego katalizatora Mg-V-Al.

20

Polyimide - silica hybrid materials

Sysel P., Pulec R., Brožová L., Pientka Z., Bleha M.

Prace Naukowe Katedry Budowy Maszyn. Seria Konferencje / Politechnika Śląska

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1998

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nr 1, t. 2

91-94

EN

Polyimide-silica hybrid films with covalently bound phases were prepared via a sol - gel process. The starting materials were p-aminophenyltrimethoxysilane terminated poly(amic acid)s of controlled molecular weight and tetramethoxysilane. The actual extent of the sol-gel process was monitored by thermogravimetric analysis. The dependence of the membrane properties on the silica content and/or concentration of bonds between phases was studied.Pč/!