Mohammed Abdallah | Sofia University "St. Kliment Ohridski" (original) (raw)

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Papers by Mohammed Abdallah

Poly sulfide-functionalized materials were synthesized by co- condensations of bis[3-(triethoxysi... more Poly sulfide-functionalized materials were synthesized by co- condensations of bis[3-(triethoxysilyl)propyl]tetrasulfide
(BTPTS) and 1,2-bis(triethoxysilyl)ethane (BTESE) in the presence of the non-ionic surfactant triblock copolymer
poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (EO20PO70EO20), Pluronic
P123. The surfactant was used as a template for improving the porosity of the hybrid gels. Samples were synthesized
with different amounts of BTPTS in acidic media. The final materials were soaked for 24 hours in ethanol and HCl
for removing P123. In this work we investigated the influence of the BTPTS amounts on the structure and morphology
of the materials after extraction of the surfactant. Samples were characterized by thermo gravimetric analysis
(DTA/TG), Fourier–transform infrared spectroscopy (FT-IR), Nitrogen adsorption-desorption measurement (BET),
Scanning electron microscopy (SEM), 13C CP MAS NMR, 29Si MAS NMR analysis and elemental analysis. The
results from 13C CP MAS NMR, 29Si MAS NMR, and FT-IR showed that the materials are hybrid organic-inorganic
materials. BET and SEM results showed that BTPTS amounts have a significant influence on the morphology and
texture parameters of the final materials. the surface area and pore volume decreased by increasing BTPTS amounts;
which make the hybrid network to be more flexible and resistant against degradation. DTA/TG results showed that,
increasing the amount of BTPTS, the thermal stability of the gel materials decreased.
Key words: Hybrid material, Mesoporous, Template, Thioether bridging group.

Sol–gel silica materials are amorphous, porous materials that have a large number of exploited an... more Sol–gel silica materials are amorphous, porous
materials that have a large number of exploited and potential
applications. In this study we report the synthesis and
characterization of porous organic-inorganic hybrid
materials which are characterized by micro and meso pores,
derived by co-condensation of tetraethoxysilane and
functionalized trialkoxysilane RSi(OR`)3. For the synthesis
tetraethyl orthosilicate (TEOS) and 3-
aminopropyltriethoxysilane (APTES) were used in acidic
medium together with amphihilic triblock-copolymer
poly(ethylene glycol)-block-poly(propylene glycol)-blockpoly(
ethylene glycol) (EO20PO70EO20), Pluronic P123 as
structure-directing agent and xylene as a swelling agent.
Inorganic salt has also been introduced in order to improve
structure ordering and to tailor framework porosity. In this
work we investigated the influence of APTES amount on the
structural properties of the resultant hybrid materials. After
solvent extraction of the P123, the resultant materials were
characterized by X-ray diffraction (XRD), Fourier-transform
infrared spectroscopy (FT-IR), 29Si MAS NMR, 13C CP
MAS NMR, and scanning electron microscopy (SEM).
Keywords: Hybrid materials, Amine-functionalized
materials, Surface functionalization; Co-condensation.

Nanoporous ceramic materials was functionalized by co-condensation of tetraethyl orthosilicate (T... more Nanoporous ceramic materials was functionalized by co-condensation of tetraethyl orthosilicate
(TEOS) and different 3-aminopropyltriethoxysilane (APTES) amounts in the presence of amphiphilic
triblock copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)
(EO20PO70EO20), who was previously dissolved in acid solution with different acid concentrations.
Pluronic P123 was used as structure-directing agent and xylene as a swelling agent. Inorganic salt
was introduced in order to improve structure ordering and to tailor framework porosity. The
synthesized materials were characterized by scanning electron microscopy (SEM), X-ray diffraction,
nuclear magnetic resonance (29Si MAS NMR and 13C CP MAS NMR), Fourier –transform infrared
spectroscopy (FT-IR) and elemental analysis. The results from NMR and FT-IR show that the organic
functional group is successfuly incorporated in the silica framework and P123 was successfully
extracted. The results from all analyzes prove that the acid concentration has significant influence on
the materials morphology and properties.
Kay words: sol-gel, mesoporous materials, hybrid materials, as structure-directing agent.

Polysulfide–functionalized mesoporous were synthesized by using co–condensations of tetraethoxyls... more Polysulfide–functionalized mesoporous were synthesized by using co–condensations of tetraethoxylsilane(TEOS) and bis[3-(triethoxysilyl)propyl]tetra sulfide (BTPTS) in the presence of nonionic surfactant triblock copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (EO20PO70EO20) Pluronic P123. The surfactant was used as template for improving the porosity of the hybrid gels. In this work we synthesized samples with different BTPTS amounts in acidic media. The final materials were soaked for 24 hours in ethanol and HCl for removing of P123. In this work we investigate the materials structure before and after extraction of the surfactant and the functional group amount incorporated in the silica framework. For this aims we used thermo gravimetric analysis (DTA/TG), Fourier–transform infrared spectroscopy (FT-IR), and elemental analysis
.Key words: Sol-gel, Hybrid Mesoporous Materials

Thioether-functionalized materials were synthesized by co-condensations of bis [3-(triethoxysilyl... more Thioether-functionalized materials were synthesized by co-condensations of bis [3-(triethoxysilyl)propyl]tetra sulfide (BTPTS) and tetraethoxylsilane (TEOS) in the presence of the nonionic surfactant triblock copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (EO 20 PO 70 EO 20 ), Pluronic P123. The surfactant was used as a template for improving the porosity of the hybrid gels. In this work we synthesized samples with different amounts of BTPTS in acidic media. The final materials were soaked for 24 hours in ethanol and HCl for removing P123. In this work we investigate structure