A glass based fibrous filler having bioactive particles such as hydroxyapatite deposited on a surface of glass fibers. Methods of preparing the fibrous filler are specified. A resin composite containing a polymerizable system reinforced with the fibrous filler, as well as a biomedical restoration based on the cured resin composite are also provided.

The invention pertains to the fields of chemistry and mechanical engineering and relates to glass fiber surfaces which are modified without sizing material and silane, which glass fiber surfaces can be further processed into and used as composite materials, for example as reinforcing fiber materials for plastics, and to a method for producing the modified glass fiber surfaces. The object of the present invention is to provide glass fiber surfaces modified without sizing materials and silane, which glass fiber surfaces exhibit improved properties overall and for a further processing into composite materials, and furthermore to provide a simple and cost-effective method for producing glass fiber surfaces modified in such a manner. The object is attained with glass fiber surfaces modified without sizing material and silane, which glass fiber surfaces are at least partially covered at least with a hydrolysis-stable and/or solvolysis-stable cationic polyelectrolyte and/or hydrolysis-stable and/or solvolysis-stable cationic polyelectrolyte mixture and/or with a hydrolysis-stable and/or solvolysis-stable polyelectrolyte complex and coupled to the glass fiber surface via a (polyelectrolyte) complex formation process by means of ionic bonding, with the polyelectrolyte complex A thereby being formed.

The invention pertains to the fields of chemistry and mechanical engineering and relates to glass fiber surfaces which are modified without sizing material and silane, which glass fiber surfaces can be further processed into and used as composite materials, for example as reinforcing fiber materials for plastics, and to a method for producing the modified glass fiber surfaces. The object of the present invention is to provide glass fiber surfaces modified without sizing materials and silane, which glass fiber surfaces exhibit improved properties overall and for a further processing into composite materials, and furthermore to provide a simple and cost-effective method for producing glass fiber surfaces modified in such a manner. The object is attained with glass fiber surfaces modified without sizing material and silane, which glass fiber surfaces are at least partially covered at least with a hydrolysis-stable and/or solvolysis-stable cationic polyelectrolyte and/or hydrolysis-stable and/or solvolysis-stable cationic polyelectrolyte mixture and/or with a hydrolysis-stable and/or solvolysis-stable polyelectrolyte complex and coupled to the glass fiber surface via a (polyelectrolyte) complex formation process by means of ionic bonding, with the polyelectrolyte complex A thereby being formed.

A glass based fibrous filler having bioactive particles such as hydroxyapatite deposited on a surface of glass fibers. Methods of preparing the fibrous filler are specified. A resin composite containing a polymerizable system reinforced with the fibrous filler, as well as a biomedical restoration based on the cured resin composite are also provided.

A glass based fibrous filler having bioactive particles such as hydroxyapatite deposited on a surface of glass fibers. Methods of preparing the fibrous filler are specified. A resin composite containing a polymerizable system reinforced with the fibrous filler, as well as a biomedical restoration based on the cured resin composite are also provided.

An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength ?, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength ?, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

A soundproofing material including a porous body having a cell structure and including inorganic fibers other than asbestos, wherein an average cell diameter is more than 300 m and 1000 m or less, a bulk density is 0.007 to 0.024 g/cm.sup.3, and a flow resistivity is 170,000 to 2,000,000 Ns/m.sup.4.

A method for forming high purity silica articles. The high purity silica articles can be particularly suitable for forming packaging such as packaging for pharmaceutical applications. The method for forming high purity silica articles can comprise, in one embodiment, (a) forming a fused quartz melt from a SiO.sub.2 raw material; (b) forming a quartz tube from the fused quartz melt; (c) treating the quartz tube with an acid composition; (d) heat treating the quartz tube subsequent to treating with the acid composition; and (e) optionally treating the quartz article with an acid composition subsequent to the heat treating operation. The method can enhance the purity of silica glass articles and products made therefrom.

The present invention relates to a process for preparing aqueous hydrolysates of aminoalkyltrialkoxysilanes by (a) initially charging water, optionally heating, (b) adding hydrolysable silanes consisting of at least one aminoalkyltrialkoxysilane in an amount which provides a molar ratio of water to total amount of aminoalkyltrialkoxysilane of 10.5 to 20, and (c) distilling off the alkyl alcohol formed in the reaction,
wherein the solids content in an aqueous composition thus prepared is 30% to 55% by weight, based on the composition, and the aqueous solution has a total content of free and bound alkyl alcohol of not more than 1% by weight, based on the composition.