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EN
The synthesis and physicochemical properties of three new complexes of vanadium at +5, +4 and +3 oxidation state are described and discussed. The octahedral surrounding of vanadium for V(III) complexes of [V(L1)(HL1)] general formula is filled with two ONO tridentate ligand L, for V(IV) one ONO ligand L, oxido ligand and 1,10-phenanthroline (phen) as a co-ligand are presented in complexes of [VO(L2)(phen)]. For V(V) the complexes of [VO2(L1)(solv)] type were formed. As ligands, the H2L Schiff bases were formed in reaction between 5-hydroxysalcylaldehyde and phenylacetic hydrazide (H2L1) and 3,5- dichlorosalicyaldehyde and 4-hydroxybenzhydrazide (L2). The magnetic moment measurements, in 8 year period, show, that V(III) complexes slowly oxidise to V(IV) with preservation of the nonoxido character of the complexes, while V(IV) complexes were found to be stable. The TG and SDTA measurements indicate, that thermal stability depends mainly on the oxidation state of vanadium. The less thermally stable are the V(V) complexes, while V(IV) and V(III) are stable up to ca. 200oC. In solution, at pH 2 (similar to that in human digestion system), again the V(IV) are the most stable, only at pH 7.0 V(III) complexes had higher stability. The most stable, thus best for pharmaceutical use, are V(IV) complexes.
2
Content available remote Influence of liming on kinetics of sewage sludge pyrolysis
EN
Thermogravimetry (TG) is the fast and reliable method for characterization of thermal decomposition of any material and in particular to determine the kinetics of pyrolytic decomposition of sewage sludge. Two types of sewage sludge with and without addition of lime were investigated from kinetic point of view. For TG analysis samples of selected sewage sludge were heated under the inert atmosphere of argon with constant heating rate from 303 to 1273 K; the three heating rate β = 5, 10 and 20 K/min were chosen. The iso-conversion methods of Friedman and Ozawa-Flynn-Wall were employed for analysis of TG results. As the sewage sludge decomposition is very complex process it cannot be described by a simple stoichiometric equation, therefore the so called lumping of reactions in the selected temperature ranges were used with detailed principles arising from visual analysis of DTG curve. The deconvolution of DTG curves performed according to Fraser-Suzuki asymmetric profile allowed the identification of number of lumps and their contribution to the overall mass loss. So the decomposition of sewage sludge with lime addition could be described with five groups of reactions while the one without lime by means of six lumps. The thermal decomposition of sewage sludge was assumed to proceed according to the scheme of parallel concurrent independent reactions of n-th order. The values of the apparent activation energies at different constant values of conversion degrees were determined by the iso-conversion analysis. To estimate the kinetic parameters the non-linear regression with Levenberg-Marquart optimization procedure was used. The kinetic parameters such as activation energy, pre-exponential factor, reaction order and fraction of total mass loss associated with a given reaction were determined. The impact of sewage sludge liming revealed in essential differences of pyrolysis products and pyrolysis kinetics of limed sludge and without lime one was highlighted.
EN
In the present paper, three kinds of aged and freshly prepared 2,4,6-trinitrotoluene (TNT) based Composition B stockpiled, for a period of 20 and 32 years, were investigated for the effect of natural ageing on their thermal degradation behaviour and kinetic parameters. The properties investigated indicated that there was no significant change in the thermal stability of the samples aged under natural environmental conditions. The kinetic parameters were studied by means of the Kissinger method using the peak temperature at maximum reaction rate from DSC data, and the isoconversional Kissinger-Akahira-Sunnose (KAS) and ASTM E689 methods from TGA data. The apparent activation energies calculated by the Kissinger method were 173.8 kJ·mol–1 for fresh, 170.4 kJ·mol–1 for 20 y old and 187.1 kJ·mol–1 for 32 y old Composition B, respectively. The values calculated by the KAS method were found to be in the range 77.2-235.8 kJ·mol–1 for fresh Composition B, 75.7-224.0 kJ·mol–1 for 20 y old and 70.4-196.0 kJ·mol–1 for 30 y old Composition B, respectively. The activation energies obtained from the KAS methods are in good agreement and consistent with the isoconversional ASTM E689 kinetic method. The thermodynamic parameters, such the Gibbs free energy of activation (ΔG#), activation enthalpy (ΔH#) and activation entropy (ΔS#) for the formation of activated complexes were also studied and are discussed.
EN
As part of the presented work, tests were carried out to check the possibility of replacing of conventional reducers used in the lead pyrometallurgical processes by cheaper, but equally effective substitutes. For research of lead oxide reduction, the following fine-grained carbonaceous materials were used, ie anthracite dust and coal flotation concentrate, as well as traditional used coke breeze for comparison. The obtained test results indicate a similar ability to reduce the lead oxide of all studied carbonaceous materials.
PL
W artykule przedstawiono wyniki prac nad właściwościami palnymi wytypowanych wykładzin wełnianych, polimerowych oraz mieszanek wełny z polimerami termoplastycznymi (PA, PP). Przeprowadzono analizę termograwimetryczną wg normy PN-EN ISO 11358:2014 oraz określono szybkość wydzielenia ciepła i dymu za pomocą kalorymetru stożkowego wg normy ISO 5660:2015. Dodatkowo wyznaczono wartości ciepła spalania z użyciem bomby kalorymetrycznej wg normy PN-EN ISO 1716:2010.
EN
The article identifies the flammable properties of the selected wool and polimer linings as well as the mixtures of the wool and thermoplastic polymers. The thermogravimetric analysis was carried out according to the PN-EN ISO 11358:2014 standard, the heat release rate and the smoke release rate were determined using a cone calorimeter according to the ISO 5660:2015 standard. In addition, the combustion heat values were determined using a calorimetric bomb according to the PN-EN ISO 1716: 2010 standard.
EN
Three products were obtained from the condensation of citric acid with: propane-1,2-diol with the catalyst Tyzor TPT (HDCA1), propane-1,2-diol without a catalyst (HDCA2) and ­propane-1,3-diol with the catalyst Tyzor TPT (HDCA3). We measured the viscosities (from 3972 mPa • s for HDCA1 to 27 986 mPa • s for HDCA3), densities (about 1200 g/cm3), hydroxyl values (280–427 mg KOH/g), and acid values (­23–52 mg KOH/g) of the HDCAs. The thermal resistance of the HDCAs were assessed under dynamic conditions. The temperature ranges of 5, 10, 20 and 50 % weight loss for HDCA polyols were, respectively: 174–194 °C, 230–234 °C, 263–303 °C, and 314–364 °C. The HDCAs were used in the further synthesis of rigid polyurethane-polyisocyanurate foams (PUR-PIR) and their physical qualities assessed with reference to foams produced from an industrial standard (Rokopol RF551). The authors examined the thermal properties (thermogravimetry, differential thermogravimetry and differential scanning calorimetry) of the foams, as well as the thermal stability: dimensional, volume and mass. The number of foam degradation stages was determined, as well as the speed of degradation of specific chemical bonds and percentage mass loss during all stages. We determined the temperature of the foam’s first weight loss, the extrapolating temperature of the foam’s weight loss, the temperature of the start of the foam’s rapid decomposition, and the temperature of the foam’s highest speed of weight loss, the temperatures of 5 %, 10 %, 20 % and 50 % mass loss were measured (respectively: 208–223 °C, 230–260 °C, 280–300 °C, 345–366 °C). The enthalpy related to each individual stage of foam degradation was examined using DSC (three endotherms and one exothermic peak).
PL
Otrzymano trzy produkty kondensacji kwasu cytrynowego z: propano-1,2-diolem w obecności katalizatora Tyzor TPT(HDCA1), propano-1,2-diolem bez katalizatora (HDCA2) oraz propano-1,3-diolem w obecności katalizatora Tyzor TPT (HDCA3). Zbadano ich lepkość (od 3972 mPa • s dla HDCA1 do 27986 mPa • s dla HDCA3), gęstość (ok. 1200 g/cm3), liczbę hydroksylową (280–427­mg KOH/g) i kwasową (23–52 mg KOH/g) oraz odporność termiczną w warunkach dynamicznych. Zmierzono temperaturę 5, 10, 20 i 50-procentowego ubytku masy polioli HDCA (odpowiednio: 174–194°C, 230–234°C, 263–303°C, 314–364°C). Wytworzone hydroksyalkilowe pochodne użyto do syntezy sztywnych pianek poliuretanowo-poliizocyjanurowych (PUR-PIR). Zbadano właściwości termiczne pianek (metodami analizy termograwimetrycznej, różnicowej analizy termograwimetrycznej i różnicowej kalorymetrii skaningowej) oraz ich stabilność termiczną: wymiarową, objętościową i masową. Określono liczbę etapów degradacji pianek, szybkość degradacji poszczególnych wiązań chemicznych i procentowy ubytek masy na wszystkich etapach, temperaturę 5, 10, 20 i 50-procentowego ubytku masy pianek (odpowiednio: 208–223°C, 230–260°C, 280–300°C, 345–366°C). Określono entalpię poszczególnych etapów degradacji pianek metodą DSC (trzech pików endotermicznych i jednego egzotermicznego).
PL
Zagadnienie sekwestracji CO2 w betonie w procesie karbonatyzacji nabiera w ostatnim czasie coraz większego znaczenia. Wynika to z faktu, iż coraz częściej zarówno konstrukcja, jak również zastosowane materiały są analizowane pod kątem ich całkowitego śladu węglowego. W artykule przedstawiono wyniki badań procesu karbonatyzacji betonu SCC C30/37 w formie gruzu betonowego frakcji 8 – 31,5 mm w komorze karbonatyzacyjnej przez okres 56, 112 i 168 dni. Próbki zostały poddane analizie spektrofotometrycznej FTIR (Fourier Transformation Infrared Spectroscopy). Następnie próbki badane przez 168 dni poddane zostały analizie termicznej TG/DTA (Thermogravimetric/Differential Thermal Analysis) w celu określenia ilości zaabsorbowanego CO2. Otrzymane wyniki zostały odniesione do maksymalnej teoretycznej ilości zaabsorbowanego CO2 wg normy PN-EN 16757-07.
EN
Issue of CO2 sequestraion in the carbonation process has become a crucial problem. This is due the fact, that construction and applied materials are analyzed in the terems of their total carbon footprint. Resutls of research on carbonation of SCC (Self-Compacting Concrete) C30/37 in the form of concrete rubble, in fraction 8 – 31,5 mm, kept for 56, 112 and 168 days have been presented in the paper. Samples were investigated with FTIR (Fourier Transformation Infrared Spectroscopy) analysis. Next, samples kept for 168 days were analyzed with thermal analysis TG/DTA (Thermogravimetric/Differential Thermal Analysis) to determine the amount of absorbed CO2. The obtained results were referred to the formula for the maximum theoretical CO2 uptake according to PN-EN 16757-07.
8
Content available remote Zastosowanie wybranych technik analizy termicznej w badaniach wyrobów lakierowych
PL
W artykule przybliżono wybrane techniki analizy termicznej: różnicowej kalorymetrii skaningowej, termograwimetrii i dynamicznej analizy mechanicznej. Omówiono zasady poszczególnych metod, techniki analizy. Podano przykłady zastosowań tych technik w analizie wyrobów lakierowych obejmujących monitorowanie różnych procesów fizykochemicznych zachodzących w powłokach, przemian fazowych w powłokach, analizę ilościową oraz charakterystykę właściwości lepkosprężystych.
EN
The article presents the selected methods of thermal analysis: differential scanning calorimetry, thermogravimetrical analysis and dynamic-mechanical analysis. The principle of the methods, measurement techniques are discussed. Examples of application of these techniques in the analysis of coatings including monitoring of various physiochemical processes occurring in coatings, phase transitions, quantitative analysis and viscouselastic properties are given.
EN
The effects of the UV radiation on the surface geometrical structure, phase transition temperatures, and the temperature of the onset of thermal decomposition of a polylactide film containing 2 wt % of dye are presented. The surface geometrical structure was examined using a scanning electron microscope (SEM) and atomic force microscope (AFM). The temperatures of both the phase transitions and the changes in the melting enthalpy of the crystalline phase were determined using a differential scanning calorimeter (DSC). The temperature of the onset of thermal decomposition of the film was determined with a thermogravimetry (TG) instrument. It was found that the UV radiation generated in an aging test chamber mostly causes changes in the surface geometrical structure of the examined film and reduces the onset temperature of the film thermal decomposition.
PL
Przedstawiono wpływ promieniowania UV na strukturę geometryczną powierzchni, temperaturę przejść fazowych i temperaturę początku rozkładu cieplnego folii polilaktydowej zawierającej 2 % mas. barwnika. Badania struktury geometrycznej powierzchni wykonano metodami skaningowej mikroskopii elektronowej (SEM) oraz mikroskopii sił atomowych (AFM). Za pomocą różnicowego kalorymetru skaningowego (DSC) wyznaczano temperaturę przejść fazowych i zmian entalpii topnienia fazy krystalicznej. Temperaturę początku rozkładu cieplnego folii badano przy użyciu termograwimetru (TG). Stwierdzono, że promieniowanie UV, generowane w komorze starzeniowej, zmienia głównie strukturę geometryczną powierzchni folii oraz obniża temperaturę początku jej rozkładu.
EN
Cobalt-based superalloys are class of new heat-resistant materials for components of turbine engines. The γ-γʹ phase microstructure similar to nickel-based analogue, provide excellent creep resistance as well as resistance to corrosion and oxidation. Superior high temperature resistance drives intensive development of Co-based superalloys. The aim of paper is assessment of high temperature oxidation behaviour of Co–9Al–9W and Co–20Ni–7Al–7W alloys in as-cast state. The non-isothermal oxidation performance of Co–9Al–9W and Co–20Ni–7Al–7W alloys was studied using thermogravimetric method up to 1200°C. The thermogravimetric analysis was carried out under argon atmosphere with heating rate 5°C/min. The scale morphology after high temperature oxidation test was investigated. The evaluation of scale concerned macrostructure, microstructure, chemical and phase composition of surface after high temperature oxidation tests. Surface of tested alloys after oxidation was characterized using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and light microscopy (LM). Co–20Ni–7Al–7W was characterized by slightly better high temperature oxidation resistance than basic Co–9Al–9W alloy. The surface stability in elevated temperature is important factor in case of components undergoing elevated temperature. This paper shows possibilities of these alloys for high temperature service.
PL
Intensywny rozwój silników lotniczych napędza poszukiwania nowych materiałów żarotrwałych, zdolnych do pracy w coraz trudniejszych warunkach. Efektem tych poszukiwań są nowe nadstopy typu γ-γʹ na bazie kobaltu, charakteryzujące się większą odpornością na utlenianie w wysokiej temperaturze od obecnie stosowanych odpowiedników na bazie niklu. Celem pracy było scharakteryzowanie utleniania nadstopu kobaltu Co–20Ni–7Al–7W w podwyższonej temperaturze i porównanie go z nadstopem bazowym Co–9Al–9W. Praca objęła badania kinetyki utleniania wysokotemperaturowego w warunkach nieizotermicznych metodą grawimetryczną oraz analizę składu chemicznego, fazowego i mikrostruktury powstałej zgorzeliny.
EN
Engine oils undergo oxidative degradation and wears out during service. Hence it is important to characterize ageing of engine oils at different simulated conditions to evaluate the performance of existing oils and also design new formulations. This work focuses on characterizing the thermo-oxidative degradation of synthetic engine oils 5W-30. Thermogravimetric analysis of fresh and degraded oil samples at different temperatures and ageing intervals was performed in STA 449 F3 Jupiter® coupled with the FTIR spectrometer. The temperature regime provided that the samples were heated to the temperature of 600°C at the heating rate of 10 K/min. Gases (nitrogen, argon) were used with flow rates of 60 mL/min. The results, along with discussion, are presented in graphs – TG curves and IR spectrum.
PL
Wstęp i cele: Artykuł ma na celu przybliżenie tematyki badania składu mieszaniny nanorurek węglowych. Z uwagi na specyfikę stosowanych metod syntezy nanorurek węglowych, otrzymany materiał zawiera wiele zanieczyszczeń. W skład mieszaniny wchodzą katalizatory oraz węgiel w różnych formach alotropowych. Również wszelkie modyfikacje surowego materiału, takie jak: oczyszczanie, separacja czy funkcjonalizacja, pociągają za sobą konieczność zbadania składu i jakości otrzymanego materiału. Materiał i metody: W pracy przedstawiono analizę materiału nanorurkowego otrzymanego metodą odparowania laserowego. W jego skład wchodzą katalizatory Ni/Co/Mo lub na bazie metali szlachetnych Pt/Re/Rh oraz węgiel amorficzny i cząstki grafitowe. W pracy przedstawiono analizę jakościową i ilościową składu mieszaniny, poddanej oczyszczaniu, separacji i funkcjonalizacji. Metody używane do określenia składu i jakości materiału to spektroskopia absorpcyjna w zakresie UV-Vis-NIR, spektroskopia ramanowska, analiza termograwimetryczna oraz transmisyjna mikroskopia elektronowa. Wyniki: Wykazano, że materiał nanorurkowy należy badać kompleksowo przy pomocy wyżej wymienionych metod w celu uzyskania kompletu informacji na temat jego składu, a tym samym jakości. Wniosek: Nie istnieje jedna metoda, dzięki której można przeanalizować wszystkie aspekty materiału nanorurkowego. Część metod pozwala na ilościowe określenie zawartości podstawowych zanieczyszczeń, podczas gdy inne pozwalają poznać morfologię i określić przydatność materiału do określonych celów.
EN
Introduction and objectives: The aim of this article is to familiarize the issue of carbon nanotubes analysis. Due to specificity of the synthesis method of carbon nanotubes the obtained material contains several kinds of impurities, such as catalysts and various carbon allotropes. Furthermore, any modifications to the raw material, such as purification, separation or functionalization, require the examination of the composition and quality of the obtained material. Material and Methods: This study presents the analysis of the nanotube material obtained by laser ablation synthesis. The material contains impurities, such as catalysts and other than nanotubes allotropes of carbon. This paper presents an qualitative and quantitative analysis of the compositions of the mixture subjected to purification, separation and functionalization. The methods used to determine the composition and quality of the material arethe absorption spectroscopy in the UV-Vis-NIR range, Raman spectroscopy, thermogravimetric analysis, and transmission electron microscopy. Results: It has been demonstrated that the nanotube material should be comprehensively examined using the abovementioned methods in order to obtain complete information on its composition and quality. Conclusion: There is no single method allowing for the analysis of all aspects of the nanotube material. Some of the methods allow for quantitative determination of the some impurities, whereas others can be used to explore the morphology of the material and to determine if material is suitable for particular purposes
13
Content available Badanie właściwości katalizatora Raney’a
PL
W pracy przeprowadzono sonochemiczną aktywację katalizatora Raney’a stosując czas ekspozycji 10 min i 20 min. Następnie suszono próbki obserwując ich zachowanie. Wykonano zdjęcia próbek stosując mikroskop optyczny, które potwierdziło wpływ sonochemicznej aktywacji na wymiar ziaren katalizatora Raney’a. Wyznaczono również zbadanie charakterystyk termiczne wytypowanych próbek. Badania przeprowadzono techniką różnicowej analizy termicznej sprzężonej z termograwimetrią (DTA/TG), za pomocą różnicowego analizatora termicznego Labsys.
EN
The sono-chemical activation of a Raney catalyst over 10 min or 20 min were performed. The samples were then dried and changes occurring during the drying process observed. Images obtained with optical microscopy confirmed the influence of sono-chemical activation on the grain size of the Raney catalyst. The thermal characteristics of the selected samples were investigated using Differential Thermal Analysis coupled with ThermoGravimetry (DTA/TG).
EN
Magnetic properties of 0.7(Fe2O3)/0.3(ZnO) nanocomposite synthesized by traditional wet chemistry method and containing only two phases: ZnO (nonmagnetic) and Zn Fe2O4 (magnetic, with nanocrystallites of average size 12 nm, but forming large agglomerates, up to 100 nm in size) were studied by DC magnetization and ferromagnetic resonance (FMR). The investigated nanocomposite was either in a form of nanopowder or dispersed at concentration of 0.1 wt.% in poly(ethylene naphthalate-block-tetramethylene oxide) PTMO-b-PEN polymer matrix. Similarities and differences in magnetic behavior of these two samples revealed by the study of static magnetization and FMR spectra have been discussed relative to different morphologies and the associated variation of interparticle interactions. Moreover, thermal and thermo-oxidative stability of the nanocomposite and the neat polymer have been studied by thermogravimetric method.
EN
Flame retardancy was imparted in cellulosic cotton textile using banana pseudostem sap (BPS), an eco-friendly natural product. The extracted sap was made alkaline and applied in pre-mordanted bleached and mercerized cotton fabrics. Flame retardant properties of both the control and the treated fabrics were analysed in terms of limiting oxygen index (LOI), horizontal and vertical flammability. Fabrics treated with the non-diluted BPS were found to have good flame retardant property with LOI of 30 compared to the control fabric with LOI of 18, i.e., an increase of 1.6 times. In the vertical flammability test, the BPS treated fabric showed flame for a few seconds and then, got extinguished. In the horizontal flammability test, the treated fabric showed no flame, but was burning only with an afterglow with a propagation rate of 7.5 mm/min, which was almost 10 times lower than that noted with the control fabric. The thermal degradation and the pyrolysis of the fabric samples were studied using a thermogravimetric analysis (TGA), and the chemical composition by FTIR, SEM and EDX, besides the pure BPS being characterized by EDX and mass spectroscopy. The fabric after the treatment was found to produce stable natural khaki colour, and there was no significant degradation in mechanical strengths. Based on the results, the mechanism of imparting flame retardancy to cellulosic textile and the formation of natural colour on it using the proposed BPS treatment have been postulated.
16
Content available remote Produkcja polihydroksymaślanu przez Cupriavidus necator
PL
W pracy zbadano produkcję polihydroksymaślanu (PHB) przez bakterie Cupriavidus necator w podłożu syntetycznym oraz w podłożu natu-ralnym w kolbach wstrząsanych. Stwierdzono, że najwięcej PHB w komórkach bakterii (62,0%) uzyskano w podłożu syntetycznym zawierającym maślan sodu o stężeniu 5 g/dm3. Przeprowadzona analiza termograwimetryczna C. necator wykazała, że jest wyraźny podział pomiędzy rozkładem termicznym PHB a pozostałymi składnikami komórek bakterii, co wskazuje na możliwość jej zastosowania do oznaczania zawartości PHB w komórkach drobnoustrojów.
EN
The production of polyhydroxybutyrate (PHB) by Cupriavidus necator in a synthetic and natural medium in shake flasks was investigated. It was found that most of PHB in bacterial cells (62.0%) was obtained in a synthetic medium containing sodium butyrate at the concentration of 5 g/dm3. The thermogravimetric analysis of C. necator showed the clear separation between the thermal degradation of PHB and other components of bacterial cells suggesting the possibility of its usage for the determination of PHB in the cells of microorganisms.
EN
The publication presents the results of thermal examinations conducted to determine of the thermal degradation of the polymeric binder (BioCo2) in the moulding sand. Thermal degradation process was identified using literature data on the decomposition of the polymers materials and based on own research (TG-DSC, MIR-DRS). In order to determine the degradation temperature and the thermal effects of transformations occurring when the moulding sand were heated, two methods were used: the thermogravimetry (TG) and differential scanning calorimetry (DSC). In this paper the spectroscopic studies (MIR-DRS) were also performed in order to elucidate structural changes occurring in the BioCo2 binder under an influence of heating. Temperature spectra were made for the moulding sand sample in the temperature range: 25-400oC (operation range of the temperature attachment of the IR spectrometer). The heating process was performed in a continuous way, and the spectra were recorded at a given temperature. On the bases of the performed thermal analysis of the moulding sand the temperature range required for the efficient thermal reclamation was indicated.
EN
Transition metal catalysts (mainly: iron, cobalt and nickel) on various supports are successfully used in a largescale production of carbon nanotubes (CNTs), but after the synthesis it is necessary to perform very aggressive purification treatments that cause damages of CNTs and are not always effective. In this work a preparation of unsupported catalysts and their application to the multi-walled carbon nanotubes synthesis is presented. Iron, cobalt and bimetallic iron-cobalt catalysts were obtained by co-precipitation of iron and cobalt ions followed by solid state reactions. Although metal particles were not supported on the hard-to-reduce oxides, these catalysts showed nanometric dimensions. The catalysts were used for the growth of multi-walled carbon nanotubes by the chemical vapor deposition method. The syntheses were conducted under ethylene - argon atmosphere at 700°C. The obtained catalysts and carbon materials after the synthesis were characterized using transmission electron microscopy (TEM), X-ray diffraction method (XRD), Raman spectroscopy and thermogravimetric analysis (TG). The effect of the kind of catalyst on the properties of the obtained carbon material has been described.
19
Content available remote Ocena odporności cieplnej nanokompozytowego lakieru poliestroimidowego
PL
Przedstawiono wyniki badań porównawczych starzenia cieplnego lakieru poliestroimidowego zawierającego 1,5%wt. nanokrzemionki płomieniowej oraz tego samego lakieru bez nanokrzemionki (lakier standardowy). Przyjęto kryteria oceny degradacji cieplnej lakieru według UL 1446, tj. wartość siły wiążącej oraz czas życia w próbie napięciowej. Dodatkowo wykonano badania termograwimetryczne lakierów w warunkach izotermicznych oraz dynamicznego nagrzewania. Uzyskane wyniki wykazują wyższą ciepłoodporność lakieru nanokompozytowego.
EN
The results of the comparative long-term thermal ageing of standard and nanofilled with 1.5% fumed nanosilica polyesterimide varnish are presented. The criteria of varnish thermal degradation according UL 1446, i.e. the bond strength value and life time at a voltage proof were assumed. In addition, the thermogravimetric TG investigations under isothermal and dynamic condition have been performed. The obtained results showed better thermal endurance of nanofilled varnish.
PL
W niniejszej pracy przedstawiono charakterystykę właściwości strukturalnych, oraz wyniki badań pojemności magazynowania tlenu, materiałów ceramicznych z grupy perowskitów podwójnych BaY1-xSmxMn2O5+δ (x = 0, 0,25, 0,5, 0,75 i 1). Podobnie jak materiał wyjściowy BaYMn2O5+δ, związki podstawiane Sm wykazują strukturę z warstwowym uporządkowaniem podsieci Ba-Y1-xSmx. Materiały zredukowane (δ ≈ 0) krystalizują w układzie tetragonalnym z grupą przestrzenną P4/nmm. W przypadku materiałów utlenionych (δ ≈ 1) zaobserwowano strukturę trójskośną P-1 dla składów o zawartości samaru x ≤ 0,5. Dla związków o zawartości x > 0,5 proces utleniania nie powoduje zmian symetrii, a materiały te różnią się od zredukowanych jedynie stopniem obsadzenia przez tlen pozycji strukturalnych oraz objętością komórki elementarnej. W przypadku całej serii materiałów zmierzono odwracalną pojemność magazynowania tlenu przekraczającą 99% wartości teoretycznej, sięgającą od 3,35% wag. dla BaSmMn2O5+δ do 3,82% wag. dla BaYMn2O5+δ. Niższa pojemność związków zawierających samar wynika z ich wyższej masy molowej. Podstawienie itru samarem istotnie wpływa na temperaturę i kinetykę procesów redukcji i utleniania, co umożliwia zaprojektowanie materiału wykazującego żądane właściwości dla zastosowań technologicznych.
EN
Characterization of structural properties and results of measurements of oxygen storage capacity of ceramic materials from the BaY1-xSmxMn2O5+δ (x = 0, 0.25, 0.5, 0.75 and 1) group of double perovskites are presented in this work. Similarly to initial BaYMn2O5+δ, Sm-substituted compounds exhibit the structure with layered arrangement of the Ba-Y1-xSmx sublattice. Reduced materials (δ ≈ 0) crystallize in tetragonal symmetry with P4/nmm space group. In the case of oxidized materials (δ ≈ 1), the triclinic P-1 structure was observed for compositions with samarium content x ≤ 0.5. For compounds with x > 0.5 the oxidation process does not cause a change of the symmetry, and these materials differ from the reduced one only by occupation of crystal positions by oxygen and by unit cell volume. In case of whole series of the materials, the measured reversible oxygen storage capacity exceeded 99% of theoretical one, which was from 3.35 wt.% for BaSmMn2O5+δ up to 3.82 wt.% for BaYMn2O5+δ. Lower capacity of Sm-containing materials was due to their higher molar mass. The substitution of yttrium by samarium significantly influenced the temperature and kinetics of reduction and oxidation, which allows for designing of material exhibiting required properties for technological applications.
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