Thermal stability of silica-coated magnetite nanoparticles prepared by an electrochemical method

Fajaroh, Fauziatul; Setyawan, Heru; Nur, Adrian; Lenggoro, I. Wuled

doi:10.1016/j.apt.2012.09.008

Cited by 61 publications

(42 citation statements)

References 11 publications

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“…The last step of nanocomposites thermal decomposition, occurring above 600°C, can be assigned to changes in the inorganic core. According to the literature, magnetite at this temperature is converted to c-hematite (maghemite, Fe 2 O 3 ) or nonstechiometric wustite Fe 1-x O [21][22][23][24][25]. Although this reaction seems more probable in the presence of air (it requires the presence of an oxidant), one may also assume that this transformation can involve oxygen atoms from CS chains or oxidizing degradation products.…”

Section: Thermogravimetric Analysis In Nitrogenmentioning

confidence: 99%

Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

Ziegler-Borowska

Chełminiak

Kaczmarek

et al. 2016

J Therm Anal Calorim

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Three different novel chitosan derivatives for medical or biotechnological applications have been successfully obtained by chemical modification of reactive amino and hydroxyl groups in chitosan chain. The modification has led to incorporation of different amount (one to three) of long-distanced amino and imine groups into each repeating unit. These highly functionalized chitosan derivatives were used as a matrix for magnetite nanoparticles. The thermal stability of all obtained chitosan materials has been determined using thermogravimetric analysis in oxidative and inert atmosphere. Chitosan containing two side substituents behaves differently from the other two, which is caused by the significant water uptake. Magnetite causes decrease in thermal stability of studied chitosan derivatives. The highest stability is observed for the nanocomposite obtained from chitosan with three side groups. The changes in the structure of the magnetite core have been observed above 600°C in nitrogen. Due to the different competitive reactions occurring in the modified chitosan, the proposed mechanism of thermal degradation is very complex.Keywords Modified chitosan Á Side group effect Á Thermogravimetric analysis Á Effect of water residue Á Thermal degradation mechanism

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Section: Thermogravimetric Analysis In Nitrogenmentioning

confidence: 99%

Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

Ziegler-Borowska

Chełminiak

Kaczmarek

et al. 2016

J Therm Anal Calorim

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“…Some of them include electrochemical method [11], laser pyrolysis [12], microemulsion synthesis [13], and hydrothermal technique [14]. In this work, we report the preparation of γ-Fe 2 O 3 nanocrystallites by co-precipitation chemical procedure.…”

Section: Introductionmentioning

confidence: 99%

Structural and Magnetic Properties of Monophasic Maghemite (γ-Fe2O3) Nanocrystalline Powder

Ramos-Guivar¹,

Martı́nez²,

Anaya³

et al. 2014

ANP

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Structural and magnetic studies of monophasic maghemite (γ-Fe2O3) magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical route are reported in this paper. For the synthesis, a starting precursor of magnetite (Fe3O4) in basic medium was oxidized at room temperature by adjusting the pH = 3.5 at 80˚C in an acidic medium without surfactants. X-ray diffraction (XRD) pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement (6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken at different temperatures show almost zero coercivity and remanence indicating superparamagnetic domain and high magnetic saturation.

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“…From the TEM image, it is found that the nanoparticle was thoroughly adsorbed in the silica shell instead of cluster formation. The calcination process could induce to transform Fe 3 O 4 (magnetite) to α-Fe 2 O 3 (hematite) or γ-Fe 2 O 3 (maghemite) [39]. We checked the Fe 3 O 4 particle crystal structure using XRD after annealing as shown in Figure 6(b).…”

Section: Hollow Silica Particle (Hsp) Formationmentioning

confidence: 99%

Fabrication of Hollow Silica Particles Using a Self-Assembled Polyethylene Granule as a Template

Park

Kim

Yoo

et al. 2018

Journal of Nanomaterials

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We developed a novel method preparing nonspherical hollow silica particles (HSP) using a micron-sized granule self-assembled from partially oxidized PE wax. The morphology of the granule was closely investigated in terms of concentration and acid value of PE wax and cooling rate. Due to the oxidized unit in PE wax, magnetic nanoparticle was incorporated into the granule during the self-assembly, and silica was coated on the granule surface via the self-assembly. Silica-coating condition was studied by varying water content and reaction time. After the PE wax was removed by calcination, nonspherical HSP or magnetic HSP was obtained. This cost-effective HSP is expected to be useful for practical applications.

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Thermal stability of silica-coated magnetite nanoparticles prepared by an electrochemical method

Cited by 61 publications

References 11 publications

Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

Structural and Magnetic Properties of Monophasic Maghemite (<i>γ</i>-Fe<sub>2</sub>O<sub>3</sub>) Nanocrystalline Powder

Fabrication of Hollow Silica Particles Using a Self-Assembled Polyethylene Granule as a Template

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Thermal stability of silica-coated magnetite nanoparticles prepared by an electrochemical method

Cited by 61 publications

References 11 publications

Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

Structural and Magnetic Properties of Monophasic Maghemite (&lt;i&gt;γ&lt;/i&gt;-Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) Nanocrystalline Powder

Fabrication of Hollow Silica Particles Using a Self-Assembled Polyethylene Granule as a Template

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Structural and Magnetic Properties of Monophasic Maghemite (<i>γ</i>-Fe<sub>2</sub>O<sub>3</sub>) Nanocrystalline Powder