Infrared Spectroscopy Studies of Aluminum Oxide and Metallic Aluminum Powders, Part I: Thermal Dehydration and Decomposition

Ludwig, Bellamarie; Burke, Taryn T.

doi:10.3390/powders1010005

Cited by 11 publications

(8 citation statements)

References 41 publications

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“…There was also a wide band in the range of wavenumbers from 700 to 1030 cm −1 , which is associated with deformation vibrations of Al-OH bonds. In the wavenumber range of 3300–3700 cm −1 , there was a wide band originating from O-H bond stretching vibrations [ 44 ]. However, the range below 3600 cm −1 belongs to the vibrations physically connected with the water surface, in which hydrogen bonds are formed between the hydroxyl groups [ 45 ].…”

Section: Resultsmentioning

confidence: 99%

Impact of Physical and Chemical Modification of the Surface of Porous Al2O3 Ceramic Membranes on the Quality of Transferred HSMG® and CVD Graphene

et al. 2023

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Graphene transfer onto ceramics, like Si/SiO2, is well-developed and described in the literature. However, it is problematic for other ceramic materials (e.g., Al2O3 and ZrO2), especially porous ones. In this case, it is mainly due to poor adhesion to the substrate, resulting in strong degradation of the graphene. For these reasons, the research topic of this study was undertaken. This article presents research on the development of the methodology of graphene transfer onto ceramic Al2O3 surfaces. Polycrystalline graphene chemical vapour deposition (CVD) monolayer and quasimonocrystalline high-strength metallurgical graphene (HSMG®) synthesised on liquid copper were used. When developing the transfer methodology, the focus was on solving the problem of graphene adhesion to the surface of this type of ceramic, and thus reducing the degree of graphene deterioration at the stage of producing a ceramic–graphene composite, which stands in the way of its practical use. Plasma and chemical ceramic surface modification were applied to change its hydrophobicity, and thus to improve the adhesion between the graphene and ceramic. The modification included the use of dielectric barrier discharge (DBD) plasma, oxygen plasma (RF PACVD method - Radio Frequency Plasma Assisted Chemical Vapour Deposition), and hydrofluoric acid treatment. Changes in surface properties caused by the modifications were determined by measuring the contact angle and (in the case of chemical modification) measuring the degree of surface development. The effectiveness of the applied surface preparation methodology was evaluated based on the damage degree of CVD and HSMG® graphene layer transferred onto modified Al2O3 using optical microscopy and Raman spectroscopy. The best average ID/IG ratio for the transferred HSMG® graphene was obtained after oxygen plasma modification (0.63 ± 0.18) and for CVD, graphene DBD plasma was the most appropriate method (0.17 ± 0.09). The total area of graphene defects after transfer to Al2O3 was the smallest for HSMG® graphene after modification with O2 plasma (0.251 mm2/cm2), and for CVD graphene after surface modification with DBD plasma (0.083 mm2/cm2).

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Section: Resultsmentioning

confidence: 99%

Impact of Physical and Chemical Modification of the Surface of Porous Al2O3 Ceramic Membranes on the Quality of Transferred HSMG® and CVD Graphene

et al. 2023

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“…It can also be seen that only few spheres are broken, leading to an irregular particle shape. On the surface of the Al 2 O 3 spheres, small sphere-shaped features are present (satellites) which are an artifact of the production method [ 30 , 31 ]. Figure 4 b,c show the graphite and expanded graphite particles, respectively.…”

Section: Resultsmentioning

confidence: 99%

Response-Surface-Methodology-Based Increasing of the Isotropic Thermal Conductivity of Polyethylene Composites Containing Multiple Fillers

et al. 2022

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To optimize the thermal conductivity of high-density polyethylene, 15 hybrid filler composites containing aluminum oxide (up to 45 m%), graphite (up to 12.5 m%), expanded graphite (up to 12.5 m%), and carbon nanotubes (1 m%), have been designed, using response surface methodology (RSM), taking into account density and melt viscosity variations. It is shown that the addition of filler(s) increases both the melt viscosity (up to ca. 270%) and the thermal conductivity (up to ca. 1000%). Hence, a further increase of TC can be hampered by a too high viscosity to enable processing. RSM indicates that all fillers have a significant effect on the thermal conductivity and synergistic effects can be achieved. The regression model obtained by applying RSM can adequately predict the thermal conductivity of composites of various compositions, as confirmed based on three validation experiments. The experimental density of the cube-shaped specimens is substantially lower than the theoretical density calculated by the linear mixing rule, mainly for the composites with high filler contents. The morphology of the composites, as studied by scanning electron microscopy (SEM), highlighted a good dispersion quality and random orientation of the fillers in the test specimens but also revealed air inclusions in the composites, explaining these density results.

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“…To obtain and analyze the vibrational spectra of the Lvf•Hh samples before and after MAct in the spectral range from 4000 to 500 cm −1 , a Fourier-transform infrared spectroscope (FTIR) (Agilent Cary 630, Santa Clara, CA 95051, USA) with a transmission attachment was used [23]. The resulting light scattering patterns were processed using ten topological descriptors similar to the Wiener (W) and Balaban (J) QSAR descriptors, modified by Trinajstic (l) (Table 1).…”

Section: Fourier-transform Ir Spectroscopymentioning

confidence: 99%

Section: Fourier-transform Ir Spectroscopymentioning

confidence: 99%

Exploring the Effects of Cramped-Impact-Type Mechanical Action on Active Pharmaceutical Ingredient (Levofloxacin)—Prospects for Pharmaceutical Applications

Uspenskaya,

Simutina,

Kuzmina

et al. 2023

Powders

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Mechanochemistry is one of the ten great discoveries of green chemistry methods for synthesizing new substances. A drug substance from the fluoroquinolone group was exposed to high-intensity mechanical impacts using a laboratory knife mill for 21 min and constantly monitored by analyzing samples extracted every 3 min with DLS, SLS, LALLS, 2D-LS, optical and digital microscopy, FTIR, and Spirotox methods. A dispersity phenomenon was detected in an area where catastrophic dislocations formed and multiplied via laser methods. The positive correlation between the temperature of deformation and stress was demonstrated, similar to a typical stress–strain curve of a Bochvar–Oding curve and Young’s modulus: the angular coefficient of the straight section to OX was tgα = 10 min−1. Z-Average, ζ-potential, and polydispersity index dependences were represented as discontinuous periodic oscillations analogous to the defect and impurity transitions near the dislocation core. Deformation r from the high-intensity mechanical impact resulted in covalent bonds showing hyper- and hypochromic effects under FTIR spectra, a bathochromic shift of the maximum, and an oscillation emission at 3240 cm−1. A 2D-LS fingerprint diagram obtained via the topological convolution of the light scattering matrix made it possible to distinguish the off-loading samples from the native substance. The investigation of the dissolution kinetics in water via laser diffraction led to conclusions about the limiting diffusion stage and the acceleration of the mechanoactivation of the solid body’s dissolution under both linear and plastic deformation. The acceleration of obsEa of the cell death process in the temperature range from 296 to 302 K indicated a significant (2.5-fold) decrease in the toxicity of the aqueous 9 mM (1:3) sample solution at 21 min compared to that of the native levofloxacin. Adherence to the mechanochemistry laws provides an opportunity for drug repositioning to change their brand status by identifying new physicochemical and biological properties.

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Infrared Spectroscopy Studies of Aluminum Oxide and Metallic Aluminum Powders, Part I: Thermal Dehydration and Decomposition

Cited by 11 publications

References 41 publications

Impact of Physical and Chemical Modification of the Surface of Porous Al2O3 Ceramic Membranes on the Quality of Transferred HSMG® and CVD Graphene

Impact of Physical and Chemical Modification of the Surface of Porous Al2O3 Ceramic Membranes on the Quality of Transferred HSMG® and CVD Graphene

Response-Surface-Methodology-Based Increasing of the Isotropic Thermal Conductivity of Polyethylene Composites Containing Multiple Fillers

Exploring the Effects of Cramped-Impact-Type Mechanical Action on Active Pharmaceutical Ingredient (Levofloxacin)—Prospects for Pharmaceutical Applications

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