Silica nanoparticles grafted with hydrophobic branches and amines may be used to mitigate corrosion. For example, method for mitigating corrosion downhole may include introducing a treatment fluid into a subterranean formation, wherein the treatment fluid includes: an aqueous acid and a plurality of silica nanoparticles grafted with hydrophobic branches and amines. Examples of amines may include C2 to C18 amines. Examples of hydrophobic branches may include C2 to C18 alkyl groups.

A composite polyvinyl alcohol (PVA) preservative film, a preparation method and an application thereof are provided. The film includes PVA of 9-12 parts, modified silicon dioxide nanoparticles of 2-5 parts, antimicrobial of 0.3-2 parts and deionized water of 100 parts. Fruits and vegetables sensitive to sunlight have lower requirements for illumination while preserving. With PVA as matrix and silicon dioxide (SiO.sub.2) nanoparticles as modified materials, composite PVA is obtained by controlling a particle size of SiO.sub.2 and modifying its surface. The composite PVA preservative film takes advantages of different refractive indexes between PVA and SiO.sub.2 and controlling the particle size of SiO.sub.2, thereby having a low luminous transmittance. The preservative film has an effect of light-proof on fruits and vegetables suitable for light-proof storage, and improves its gas transmission and water resistance because of adding SiO.sub.2, thereby facilitating packaging preservation of the fruits and vegetables.

Spherically-shaped silica can include a precipitated silica powder having a d.sub.50 particle size selected within a range of greater than 20 ?m and up to 80 ?m, a di-octyl adipate oil absorption selected within a range of from 150 ml/100 g to 500 ml/100 g, an average circularity selected within a range of from 0.70 to 1.0, and an angle of repose, of less than 30?. A process of preparing spherically-shaped silica powder is also included.

In order to provide a filler composition for fabricating a high-performance filler achieving good productivity while preventing worsening of a working environment and production of a VOC and to provide a filler and a method for producing the filler, a filler composition of the present invention contains wet silica, a polyoxyethylene unsaturated fatty acid ester, and a sulfur-containing silane coupling agent.

Disclosed in certain embodiments are polymer compositions comprising closed-cell metal oxide particles and methods of preparing the same. In at least one embodiment, a closed-cell metal oxide particle comprises a metal oxide matrix defining an array of closed-cells. Each closed-cell encapsulates a media-inaccessible void volume. The outer surface of the closed-cell metal oxide particle is defined by the array of closed-cells.

The invention relates to a process for treatment of a natural clay material comprising sodium bentonite comprising i) Preparing an aqueous slurry of a natural clay material comprising sodium bentonite, ii) Removing non-sodium bentonite impurities from the aqueous slurry, and iii) Removing water from the aqueous slurry by spray drying in a spray drying apparatus to prepare a solid treated sodium bentonite clay.

The present invention related to a hollow silica particle including: a shell layer containing silica; and a space formed inside the shell layer, in which the hollow silica particle has a particle density as measured by a dry pycnometer density measurement using helium gas of 2.00 g/cm.sup.3 or more and a particle density as measured by a dry pycnometer density measurement using oxygen gas of lower than 2.00 g/cm.sup.3.

Silica nanoparticles grafted with hydrophobic branches and amines may be used to mitigate corrosion. For example, method for mitigating corrosion downhole may include introducing a treatment fluid into a subterranean formation, wherein the treatment fluid includes: an aqueous acid and a plurality of silica nanoparticles grafted with hydrophobic branches and amines. Examples of amines may include C2 to C18 amines. Examples of hydrophobic branches may include C2 to C18 alkyl groups.

Provided is a silica that exhibits a high matting property when utilized as a matting agent for a paint, and can also suppress the occurrence of cloudiness. The silica has an aggregated structure in which primary particles are aggregated, has a particle diameter ratio R represented by the following equation (1) of from 4.3 to 5.2, has an absorbance of 0.6 or less for light having a wavelength of 700 nm as an aqueous dispersion having a concentration of 1.48 mass %, and has a particle density measured with a He pycnometer of 2.18 g/cm.sup.3 or more: Equation (1) R=.sup.LD50/.sup.CD50 (in the equation (1), .sup.LD50 represents a volume-based 50% cumulative particle diameter (m) of the silica measured based on a laser diffraction/scattering method, and .sup.CD50 represents a volume-based 50% cumulative particle diameter (m) of the silica measured based on a Coulter counter method).