Provided is silica powder that, when used as a resin filler such as a semiconductor sealant, allows for obtaining a resin composition having excellent gap permeability and low viscosity. The silica powder is such that (1) a cumulative 50% mass diameter D.sub.50 of a mass-based particle size distribution obtained by a centrifugal sedimentation method is 300 nm to 500 nm (preferably, 330 nm to 400 nm), (2) a loose bulk density is 250 kg/m.sup.3 to 400 kg/m.sup.3 (preferably, 270 kg/m.sup.3 to 350 kg/m.sup.3), and (3) {(D.sub.90?D.sub.50)/D.sub.50}?100 is 30% to 45%. In a silica production method in which a silicon compound is burned, silica powder can be produced by installing a burner having a concentric multiple pipe structure of three or more pipes in a reactor which has a cooling jacket portion provided around the burner, and adjusting flame combustion conditions and cooling conditions.

Provided is a calcium carbonate that comprises crystals having a particular shape and structure and has a nano-order average particle size. Provided are a method for producing a calcium carbonate that comprises crystals having a particular shape and structure and has an average particle size in a particular range and a crystal growth method. The calcium carbonate has the calcite structure, has a BET specific surface area of 2 to 50 m.sup.2/g, has a number-based average particle size of 30 nm to 1.0 ?m as determined by electron microscopy, and partially comprises substantially ring-like particles.

Provided is a calcium carbonate that comprises crystals having a particular shape and structure and has a nano-order average particle size. Provided are a method for producing a calcium carbonate that comprises crystals having a particular shape and structure and has an average particle size in a particular range and a crystal growth method. The calcium carbonate has the calcite structure, has a BET specific surface area of 2 to 50 m.sup.2/g, has a number-based average particle size of 30 nm to 1.0 ?m as determined by electron microscopy, and partially comprises substantially ring-like particles.

A polycrystalline ferrite composition comprises a formula of M.sub.5Me.sub.2Ti.sub.3Fe.sub.12O.sub.31, wherein M is Ba.sup.2+, Sr.sup.2+, or a combination thereof; and Me is Mg.sup.2+, Zn.sup.2+, Cu.sup.2+, Co.sup.2+, or a combination thereof; and has an average grain size of 1 micrometer to 100 micrometers. A composite comprises a polymer matrix; and the polycrystalline ferrite composition. Methods of making the polycrystalline ferrite composition and the composite are also disclosed.

A polycrystalline ferrite composition comprises a formula of M.sub.5Me.sub.2Ti.sub.3Fe.sub.12O.sub.31, wherein M is Ba.sup.2+, Sr.sup.2+, or a combination thereof; and Me is Mg.sup.2+, Zn.sup.2+, Cu.sup.2+, Co.sup.2+, or a combination thereof; and has an average grain size of 1 micrometer to 100 micrometers. A composite comprises a polymer matrix; and the polycrystalline ferrite composition. Methods of making the polycrystalline ferrite composition and the composite are also disclosed.

A composition for a metal surface coating that does not require a posttreatment such as heating, has flexibility to be able to follow deformation of a member to be coated, hardly peels off from a metal surface, and can be used for the purpose of corrosion protection, and a terminal-equipped covered electric wire using the same. The composition contains an adduct and a base oil. The adduct contains an acidic phosphate ester consisting of one or more kinds of compounds represented by General Formulae (1) and (2), and a metal, P(O)(OR.sub.1)(OH).sub.2 . . . (1), P(O)(OR.sub.1).sub.2(OH) . . . (2), where R.sub.1 represents a hydrocarbon group having 4 to 30 carbon atoms.

A composition for a metal surface coating that does not require a posttreatment such as heating, has flexibility to be able to follow deformation of a member to be coated, hardly peels off from a metal surface, and can be used for the purpose of corrosion protection, and a terminal-equipped covered electric wire using the same. The composition contains an adduct and a base oil. The adduct contains an acidic phosphate ester consisting of one or more kinds of compounds represented by General Formulae (1) and (2), and a metal, P(O)(OR.sub.1)(OH).sub.2 . . . (1), P(O)(OR.sub.1).sub.2(OH) . . . (2), where R.sub.1 represents a hydrocarbon group having 4 to 30 carbon atoms.

Hydrotetrazine compounds having antioxidant properties and uses thereof are described herein. These compounds may be dihydrotetrazines, tetrahydrotetrazines, or hexahydrotetrazines that can be utilized as antioxidants for use in thermoplastics, thermosets and elastomers; free radical inhibitors to stabilize reactive chemicals, such as monomers against free radical polymerizations; and as anticorrosion agents in coatings to protect against metal oxidation. The hydrogenated tetrazines can donate hydrogen atom equivalents to terminate radical chain reactions. These compounds can change colors to signal when oxidation has occurred, and can be further recycled by reduction reactions.

Hydrotetrazine compounds having antioxidant properties and uses thereof are described herein. These compounds may be dihydrotetrazines, tetrahydrotetrazines, or hexahydrotetrazines that can be utilized as antioxidants for use in thermoplastics, thermosets and elastomers; free radical inhibitors to stabilize reactive chemicals, such as monomers against free radical polymerizations; and as anticorrosion agents in coatings to protect against metal oxidation. The hydrogenated tetrazines can donate hydrogen atom equivalents to terminate radical chain reactions. These compounds can change colors to signal when oxidation has occurred, and can be further recycled by reduction reactions.

A method for preparing blends of at least two polymer components is described herein. The disclosed method generally involves controlling relative molecular weights and ratios of the two or more polymer components by selecting a first initiator, a second initiator, and a monomer, and subjecting the reactants to conditions suitable to polymerize the monomer based at least in part on the first and second initiators in connection with obtaining the polymeric blend. The second initiator is advantageously selected based on one or more characteristics associated therewith, based on a characteristic of the first initiator. A polymeric blend produced according to such a method is also provided herein.