The present invention is drawn to a method of treating silica in an aqueous environment. The method can comprise steps of dispersing silica particulates in an aqueous environment to form an aqueous dispersion; reversing the net charge of a surface of the silica particulates from negative to positive using a surface activating agent, thereby forming surface-activated silica particulates dispersed in the water; and contacting the surface-activated silica particulates with organosilane reagents to form reagent-modified and surface-activated silica particulates.

Provided herein is a multifunctional particle and methods of forming the same. The multifunctional particle includes: a silica particle; a hydrophobic silane; and a silane coupling agent; where each of the hydrophobic silane and the silane coupling agent are chemically bonded to the surface of the silica particle; where the multifunctional particle is superhydrophobic and chemically reactive.

Provided herein is a multifunctional particle and methods of forming the same. The multifunctional particle includes: a silica particle; a hydrophobic silane; and a silane coupling agent; where each of the hydrophobic silane and the silane coupling agent are chemically bonded to the surface of the silica particle; where the multifunctional particle is superhydrophobic and chemically reactive.

The invention relates to a process for preparing a silane, to a process for modifying a silica with the silane, and to a modified silica. The process for preparing a silane of the formula I) comprises at least the following steps: a) providing a substance (R.sup.1).sub.oSi—R.sup.2—HNC(═O)NH-A-NH.sub.2; b) providing a substance HOC(═O)-A-S.sub.2-A-C(═O)OH; c) activating the substance from step b) through reaction with oxalyl chloride to form ClC(═O)-A-S.sub.2-A-C(═O)Cl; d) reacting at least two equivalents of the substance from step a) with one equivalent of the substance from step a), thereby obtaining a silane of the formula I); e) optionally purifying the silane of the formula I) obtained in step d)
(R.sup.1).sub.oSi—R.sup.2—HNC(═O)NH-A-HNC(═O)-A-S.sub.k-A-C(═O)NH-A-NHC(═O)—R.sup.2—Si(R.sup.1),  I)
wherein the groups A within a molecule may be identical or different and are aromatic groups.

The problem to be solved by the present invention is to provide colloidal silica for metal polishing that is capable of achieving a high polishing rate. This problem can be achieved by a colloidal silica for metal polishing, comprising a silica particle having a surface on which a functional group having at least one carboxyl group is immobilized by covalent bonding.

A dispersion liquid contains modified silica particles that are obtained by reacting silica particles which are surface-treated with a compound A represented by Formula Si(R.sup.A).sub.4-n(X.sup.A).sub.n, which has a reactive group, with a compound B which has a functional group reacting with the reactive group to form a bond and has an organic group, an organic solvent, and water, in which a content of water is 0.1 to 20.0 mass % with respect to a total mass of the modified silica particles. In Formula A, R.sup.A represents a monovalent organic group including the reactive group, X.sup.A represents a hydroxyl group or a monovalent hydrolyzable group, and n represents an integer of 1 to 3.

A dispersion liquid contains modified silica particles that are obtained by reacting silica particles which are surface-treated with a compound A represented by Formula Si(R.sup.A).sub.4-n(X.sup.A).sub.n, which has a reactive group, with a compound B which has a functional group reacting with the reactive group to form a bond and has an organic group, an organic solvent, and water, in which a content of water is 0.1 to 20.0 mass % with respect to a total mass of the modified silica particles. In Formula A, R.sup.A represents a monovalent organic group including the reactive group, X.sup.A represents a hydroxyl group or a monovalent hydrolyzable group, and n represents an integer of 1 to 3.

The present invention relates to spherical, dense micrometre-sized particles comprising colourants. The invention also relates to a material comprising these particles intended for use in papermaking, paint, agri-food, cosmetics or pharmaceuticals. It also relates to the process for preparing these particles and their incorporation in a matrix.

Core particles produced in situ or introduced as preformed core particles are coated with a layer of carbon. Non-carbon as well as some carbon-based core materials can be utilized. The resulting carbon coated particles can find applications in rubber products, for instance as reinforcement for tire components.

Metal oxide-polymer composite particles have a median particle size D50 of 40-75 nm or 100-150 nm and an average RTA of at least 0.06. Alternatively or in addition, metal oxide-polymer composites comprise two or more populations of metal oxide particles differing in size, particle size distribution, or shape. Alternatively or in addition, the use of a multicomponent hydrophobizing system including an alkylsilane to fabricate metal oxide-polymer composite particles increases the tribocharge of the composite particles.