The invention relates to a novel process for preparing a precipitated silica, in which: a silicate is reacted with an acidifying agent, so as to obtain a suspension of precipitated silica, said suspension of precipitated silica is filtered, so as to obtain a filter cake, said filter cake is subjected to a liquefaction operation, after the liquefaction operation, a drying step is performed,
characterized in that at least one polycarboxylic acid is added to the filter cake, during or after the liquefaction operation.

The invention also relates to novel precipitated silicas and to uses thereof.

A method for coating a surface of fused silica material is provided. A surface of a piece of material is pre-conditioned with a hydrolyzing reagent creating an SiOH or ROH bond on the surface. The surface is covered with thionyl chloride for a predetermined amount of time converting the SiOH bond on the surface to an SiCl. The thionyl chloride is removed and the surface is covered with a compound or mixture having an amine group converting the SiCl bond to an SiNR bond. The compound or mixture is removed.

A fire retardant material includes a deconstructed nanoporous material including a plurality of elements, and solids of a fire-retarding solution within the elements of the nanoporous material. A method of forming the fire retardant material includes combining a nanoporous material and a fire-retarding solution such that elements of the nanoporous material absorb the fire retarding solution, and evaporating liquid from the elements of the nanoporous material having the fire-retarding solution absorbed therein such that a concentrate or solids thereof remain within the elements of the nanoporous material.

A method for manufacturing a low dielectric silica powder incudes heat-treating a silica powder at a temperature of 500 C. to 1500 C. to achieve 0.0005 or less of a dielectric loss tangent of the silica powder at 10 GHz, and etching a surface of the heat-treated silica powder with an etching solution. A silica powder with an extremely small dielectric loss tangent, a resin composition containing the same, and a method for manufacturing a silica powder with a low dielectric loss tangent and strong adhesion at the interface to resin are achieved.