Презентация на тему: Nanofibers of aluminum oxide

Nanofibers of aluminum oxide
Nafen is produced from melt: industrial-scale technology
TEM micrographs / SAXS data
Nafen nanofibers : summary of properties
Is it unique?
Mechanical properties of individual fiber
Phase analysis (XRD )
High-temperature phase transformation ( XRD)
The surface is ‘saw-shaped’ (TEM)
EP-PP copolymers: “as co-monomer”
Technological challenges & solutions
Surface chemistry
Nafen as support for heterogeneous catalysts: first trials
Nafen as support for heterogeneous catalysts: potential / advantages
Nanofibers of aluminum oxide
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Первый слайд презентации: Nanofibers of aluminum oxide

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Слайд 2: Nafen is produced from melt: industrial-scale technology

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Слайд 3: TEM micrographs / SAXS data

small-angle scattering (SAXS); also indicate high degree of alignment

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Слайд 4: Nafen nanofibers : summary of properties

Parameter value Phase gamma / chi ~ 15:85 * Mean fiber diameter, nm 7-10 Fiber length, mm 1–150 Specific surface area (BET), m 2 /g 100-150 Purity, % 99.7 Bulk density, g / cm 3 0.1 to 0.4 * - phase composition can not be accurately quantified because of lack of structure model for -phase

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Слайд 5: Is it unique?

Reference 1: AlOOH “ aerogel ” (FEI) Reference 2: Nano Technology Inc. (Korea): “diameter is approximately 5-10 nm, and the aspect ratio is in the 50 to 200 range” 200nm 99360 : 1 AL2O3 (Alumina) Nanotubes

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Слайд 6: Mechanical properties of individual fiber

CNTs (Wiki): Young's modulus on the order of 270 - 950 GPa and tensile strength of 11 - 63 GPa

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Слайд 7: Phase analysis (XRD )

Typical diffraction patterns for low-temperature phases of alumina chi is identified by the peak at 2 = 42.8 Diffraction patterns of two samples of Nafen the phase is identified as mostly chi, with some gamma crystallite (CSR) size 50-100 nm Nafen fibers are polycrystalline alumina in gamma and chi phases

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Слайд 8: High-temperature phase transformation ( XRD)

At 1200–1400 C, transformation to alpha phase occurs

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Слайд 9: The surface is ‘saw-shaped’ (TEM)

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Слайд 10: EP-PP copolymers: “as co-monomer”

Surface treatment type affects the performance, including level of TOD stability enhancement 790% / 5.8 MPa 94 0% / 8.0 MPa Main application: reinforcing filler for thermoset-based adhesives Refefence : N.M. Bravaya et al., J. Appl. Polymer Sci. (2017) – accepted for publication

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Слайд 11: Technological challenges & solutions

Ultrasonic dispersion and/or targeted surface treatment (functionalization) allows good (almost to single fiber) level of dispersion

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Слайд 12: Surface chemistry

1 H MAS NMR: three types of surface protons: - terminal - bridge - hydrogen-bonded IR spectroscopy / CO absorption: only weak and medium-strength Brønsted and Lewis centers are present: max Q(LC) = 39 kJ/mole - considerably lower than for “conventional” Al 2 O 3 types

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Слайд 13: Nafen as support for heterogeneous catalysts: first trials

1) HDC of halogen-aromatic compounds: application for waste treatment ( unpublished ) Cl -benzene cyclohexane benzene Temperature 2) Emulsion hydrogenation of substituted phenols (unpublished data): 23 compounds tested Nafen-supported catalyst showed up to 95% yield and up to 94% selectivity 2) Low-temp CO-oxidation 95% conversion already with unmodified commercial catalyst

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Слайд 14: Nafen as support for heterogeneous catalysts: potential / advantages

low-T Al 2 O 3 polymorph relatively high SSA and “h ighly-defective” surface: allows easy anchoring of catalytically active components low acidity: no / minimal side reactions  selectivity surface chemistry can be tailored: - three subtypes of Nafen available - functionalization is possible ready masterbatches for liquid dispersion type processes can be produced “bonus” reinforcement effect (?)

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Последний слайд презентации: Nanofibers of aluminum oxide

Thank You for Attention

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