Structural Investigation of Hydrous TiO<sub>2</sub> Precipitates and Their Aging Products by X-ray Diffraction, Atomic Force Microscopy, and Transmission Electron Microscopy

Jalava, Juho-Pertti; Heikkilä, L.; Hovi, Oskari; Laiho, R.; Hiltunen, E.; Hakanen, Arvi; Härmä, Harri

doi:10.1021/ie970469b

Cited by 15 publications

(14 citation statements)

References 21 publications

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“…Water molecules are directly bonded to the terminal OH groups by hydrogen bonding. These water molecules link to the other water molecules via hydrogen bonds . Hence, the titania gel in this study can be called hydrous titania gel and described as TiO 2 · n H 2 O, or more precisely as TiO 2− x (OH) 2 x ·( n − x )H 2 O.…”

Section: Resultssupporting

confidence: 68%

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Preparation of Highly Crystallized Strontium Titanate Powders at Room Temperature

et al. 2015

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Highly crystallized fine powder of strontium titanate (SrTiO 3 ) was obtained at room temperature simply by leaving a vial containing the powder mixture of Sr(OH) 2 Á8H 2 O and hydrous titania gel (TiO 2 ÁnH 2 O) for 10 d. Solvent and additive(s) used in the conventional low-temperature process were not used. The crystallinity judged from the FWHM of X-ray diffraction peak was comparable to that obtained by a solid-state reaction. To cause the reaction at room temperature, the titania gel had to contain a considerable amount of H 2 O (n > 0.97). The reaction is considered to be neutralization of titanic acid [H 4 TiO 4 or Ti (OH) 4 ] and strontium hydroxide (base). Using similar process, highly crystallized BaTiO 3 powder was also obtained at 60°C. In comparison with the formation temperature of BaTiO 3 , tolerance factor in the perovskite structure was important for the room-temperature synthesis of SrTiO 3 . SrTiO 3 was hardly obtained at room temperature by the addition of saturated strontium hydroxide solution to the hydrous TiO 2 gel (n = 1.29). Therefore, the reaction seems to proceed in the hydrous titania gel. This process is characterized by three important points; "no solvent", "no additional reagents", and above all, "no heating".

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Section: Resultssupporting

confidence: 68%

“…These water molecules link to the other water molecules via hydrogen bonds. [19][20][21][22] Hence, the titania gel in this study can be called hydrous titania gel and described as TiO 2 ÁnH 2 O, or more precisely as TiO 2Àx (OH) 2x Á(nÀx)H 2 O. The n value depends on the extent of polymerization of Ti (OH) 4 .…”

Section: Resultsmentioning

confidence: 99%

Preparation of Highly Crystallized Strontium Titanate Powders at Room Temperature

et al. 2015

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“…The formation of an admixture of brookite in anatase in aged samples obtained from alkaline media has been already noticed in Ref. [16]. The crystallite size determined by means of the Scherrer method gives R cryst = 3 nm (Table 1).…”

Section: Resultssupporting

confidence: 55%

Hydrothermal synthesis of anatase nanoleaves and size dependence of anatase–rutile transformation upon heating

Lisnycha¹,

Kirillov

Potapenko

et al. 2016

Int Nano Lett

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Amorphous TiO 2 obtained by adding TiCl 4 to an alkaline medium crystallizes slowly and upon 3 years ageing transforms to nanosized anatase containing an admixture of brookite. The hydrothermal treatment of this sample in solutions of lithium hydroxide leads to anatase nanoleaves, and the more concentrated LiOH solution, the greater the nanoleaves and the smaller their specific surface area. The thermal treatment of nanoleaves leads to the bulk rutile, and the greater the specific surface area of anatase nanoleaves, the lower the anatase-rutile transition temperature. This is in line with conclusions based on the thermodynamic stability of nanosized anatase over the bulk rutile.

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“…Characteristics peaks were noted at higher concentrations of nHA rather than at lower concentrations of nHA. It is noteworthy that the crystalloid characteristics were masked by gelatin at low concentrations of nHA, indicating that gelatin could reduce the crystalloid properties (Jalava et al, ). Therefore, our results were similar to results reported in another study, which revealed that chitosan could reduce the crystal growth of nHA (Dumont et al, ).…”

Section: Resultsmentioning

confidence: 99%

Improved mechanical and thermal properties of gelatin films using a nano inorganic filler

Liu

Wang

et al. 2016

J Food Process Engineering

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To fabricate gelatin films with excellent mechanical and thermal properties, nanoscale hydroxyapatite (nHA) was introduced into a gelatin matrix. The effect of added nHA content (0-20 wt %) on the physicochemical properties of the nHA-gelatine films was investigated. Morphology analyses confirmed that the nHA particles were tightly and uniformly incorporated into the gelatin matrix. The thickness, water vapor permeability, light transmission, and moisture content of the films varied considerably depending on the added nHA amount. The addition of 15 wt % nHA increased the tensile strength of the gelatin films to 58.38 MPa but decreased the elongation to 27.85%. Furthermore, adding nHA improved the thermal properties, with the highest melting temperature of 80.98°C for the 10 wt % nHA-reinforced film. Few changes in the conformation of the gelatin molecule were observed. Therefore, based on the particle nature and good compatibility with gelatin, nHA reinforcement provides a potential approach to improve gelatin film performance in food packaging field. Practical ApplicationsTo improve the performance of gelatin films and to fabricate gelatin films with great mechanical and thermal properties, nanoscale hydroxyapatite (nHA), which was used to fabricate biomaterials with excellent mechanical properties, added into a gelatin matrix to produce nHA-gelatin films.The aim of this article is to explore the potential application of the nHA-gelatin composite film in mainly food-contacted packing material field, focusing on its corresponding properties, such as mechanical characteristics, barrier capacity, thermostablity, and so on. It is different from the previous researches, with an emphasis on bio-material properties. Therefore, the biocompatible and biodegradable gelatin-nHA composite films were developed in this study. K E Y W O R D Sfood packaging, gelatin, hydroxyapatite, nano-reinforcement

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Structural Investigation of Hydrous TiO₂ Precipitates and Their Aging Products by X-ray Diffraction, Atomic Force Microscopy, and Transmission Electron Microscopy

Cited by 15 publications

References 21 publications

Preparation of Highly Crystallized Strontium Titanate Powders at Room Temperature

Preparation of Highly Crystallized Strontium Titanate Powders at Room Temperature

Hydrothermal synthesis of anatase nanoleaves and size dependence of anatase–rutile transformation upon heating

Improved mechanical and thermal properties of gelatin films using a nano inorganic filler

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Structural Investigation of Hydrous TiO2 Precipitates and Their Aging Products by X-ray Diffraction, Atomic Force Microscopy, and Transmission Electron Microscopy

Cited by 15 publications

References 21 publications

Preparation of Highly Crystallized Strontium Titanate Powders at Room Temperature

Preparation of Highly Crystallized Strontium Titanate Powders at Room Temperature

Hydrothermal synthesis of anatase nanoleaves and size dependence of anatase–rutile transformation upon heating

Improved mechanical and thermal properties of gelatin films using a nano inorganic filler

Contact Info

Product

Resources

About

Structural Investigation of Hydrous TiO₂ Precipitates and Their Aging Products by X-ray Diffraction, Atomic Force Microscopy, and Transmission Electron Microscopy