Precipitated silica

About: Precipitated silica is a research topic. Over the lifetime, 1401 publications have been published within this topic receiving 20992 citations.

Kinetic study of Fe removal from precipitated silica prepared from yellow phosphorus slag

Abstract: This purification process may be described by the unreacted shrink core model with solid resultant (inert material) and fixed particle size, which is carried out by the action of nitric acid solution on the precipitated silica obtained from yellow phosphorus slag which was leached with phosphoric acid. The study results indicate that the purification process is a chemical reaction controlling step and its apparent activation energy E a is 30.354 kJ/mol, with reaction order 0.6746.

Use of Antioxidant-modified Precipitated Silica in Natural Rubber

Abstract: Fillers play a dominant role in modifying the properties of the base polymer. Precipitated silica is a promising non-black filler for rubber vulcanisates. As silica is hydrophilic and rubber is hydrophobic, uniform dispersion of silica in rubber is difficult and gives rise to problems such as high initial viscosity. Silica has a number of hydroxyl groups, which result in filler―filler particle agglomeration and reagglomeration. Incorporation of silica into rubber is quite difficult compared with the incorporation of carbon black. The main aim of this study was to reduce the hydrophilicity of silica by coating antioxidant onto its surface, and hence achieve easy incorporation of silica into rubber. The preparation of antioxidant-modified precipitated silica and its use as filler in rubber compounds were investigated. The curing and mechanical properties of the compounds were compared with those of conventional compounds containing unmodified silica and antioxidant in the same dosage on natural rubber. The cure and mechanical properties were found to be superior for modified silica composites compared with unmodified silica composites.

Organic plant derived precipitated silica aggregates, elastomers reinforced therewith and articles such as tires with component thereof

Abstract: The invention relates to preparation of plant-derived synthetic silica aggregates from organic plant sources, (e.g. rice husks), reinforcement of rubber compositions therewith and preparation of articles of manufacture, such as tires, having at least one component, (e.g. treads), as a rubber composition which contains said plant-derived precipitated silica aggregates. The invention further relates to such plant-derived silica aggregates having been pre-treated with an alkylsilane and/or organomercaptosilane. The invention additionally relates to the preparation of rubber compositions therewith with an addition of a starch/plasticizer composite. The invention further relates to preparation of articles of manufacture, including tires, having at least one component comprised of such prepared rubber composition such as, for example, tires having such components as treads, sidewalls and/or innerliners.

Viscosity-modifying silica materials that exhibit low cleaning and abrasive levels and dentifrices thereof

Abstract: Unique abrasive and/or thickening materials that are in situ generated compositions of precipitated silicas and silica gels are provided. Such compositions exhibit different beneficial characteristics depending on the structure of the composite in situ generated material. With low structured composites (as measured via linseed oil absorption levels from 40 to 100 ml oil absorbed/100 g composite), simultaneously high pellicle film cleaning properties and moderate dentin abrasion levels are possible in order to accord the user a dentifrice that effectively cleans tooth surfaces without detrimentally abrading such surfaces. Increased amounts of high structure composite materials tend to accord greater viscosity build and thickening benefits together with such desirable abrasion and cleaning properties, albeit to a lesser extent than for the low structure types. Thus, mid-range cleaning materials will exhibit oil absorption levels from an excess of 100 to 150, and high thickening/low abrasion composite exhibit oil absorption properties in excess of 150. Such an in situ, simultaneously produced precipitated silica/silica gel combination provides such unexpectedly effective low abrasion and high cleaning capability and different thickening characteristics as compared to physical mixtures of such components. Encompassed within this invention is a unique method for making such gel/precipitated silica composite materials for such a purpose, as well as the different materials within the structure ranges described above and dentifrices comprising such.

Aqueous suspension of silica and of aluminium sulphate or of alum, processes for the preparation and uses of the said suspension

Abstract: The invention relates to aqueous suspensions of precipitated silica and of aluminum sulphate which have a pH lower than 4 and a solids content of between 10 and 50% by weight and which, after a period at rest of 48 hours, are in the form of a gel. The gel is reversible under low shear. The invention also relates to processes for the preparation of these suspensions and to their uses, especially in the field of cement mixes, mortars and concretes.