Precipitated silica

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

Lead acid battery with gelled electrolyte formed by filtration action of absorbent separators, electrolyte therefor, and absorbent separators therefor

Abstract: A method for producing a lead acid battery that operates on the oxygen cycle is disclosed. The method includes the steps of: assembling a cell comprising a positive plate, a negative plate, and a sheet of separator material which is an absorbent, porous filtration medium, so that there is free space between the plates and surfaces of the separator; inserting the cell into a case, introducing into the case a mixture of sulfuric acid and silica including silica from a never dried precipitated silica slurry, causing the sulfuric acid in the mixture in the free space to gel, and sealing the case. The sulfuric acid in the mixture in the free space can be caused to gel by an increase in the silica content thereof, by an increase in the specific gravity thereof, or by both an increase in the silica content thereof, and an increase in the specific gravity thereof.

Precipitated Silica from Wheat Husk

Abstract: In present investigation extraction of amorphous silica from wheat husk and then converting it into precipitated silica by using sodium hydroxide has been studied at various Na/Si ratios and reaction time. Wheat husk was calcined in electric tube furnace at 500 0 C for two hours to produce wheat husk ash (WHA). XRD of WHA confirmed its amorphous nature. The WHA was treated against sodium hydroxide at different molar ratios and reaction time to obtain sodium meta silicate. Each time sodium meta silicate was treated against 0.1N HCl to recover silica in precipitated form. XRD and FTIR results confirmed the amorphous nature of precipitated silica. It was also observed that one hour boiling with molar ratio Na/Si =2 is sufficient for optimum conversion into sodium meta silicate.

Contribution of hydrogen and/or covalent bonds on reinforcement of natural rubber latex films with surface modified silica

Abstract: A macromolecular coupling agent containing hydrophilic and hydrophobic groups is made to react with precipitated silica. Interfacial interactions between OH groups of silica and COOH groups of macromolecule are found to be created through either hydrogen bonds alone or through hydrogen bonds and covalent bonds. Aqueous dispersions of unmodified and modified silica are prepared and the colloidal stability and particle size distribution of the dispersions are observed. The dispersions at neutral pH are incorporated into vulcanized/unvulcanized natural rubber latex. The formation of hydrogen bonds and/or covalent bonds is studied via FTIR spectroscopy and their contribution in encouraging filler-rubber interactions is emphasized through mechanical and swelling properties. Uniform distribution and dispersion of modified filler particles throughout the rubber matrix is confirmed by the microstructures of the latex films cast from filler added natural rubber latex. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40380.

Pure Silica Extraction from Perlite: ItsCharacterization and Affecting factors

Abstract: A simple method based on alkaline extraction followed by acid precipitation and acid dissolution has been developed to produce pure amorphous silica from perlite. The reaction parameters such as molar ratio of NaOH/SiO2, reaction time and reaction temperature are varied for obtaining maximum silica conversion. About 70.6 % pure precipitated silica from perlite has been achieved in closed system at 120 oC within 60 min. XRF, BET surface area, XRD, FTIR and SEM techniques are used to characterize the physico-chemical attributes of materials. The present research includes a cost benefit process under optimized conditions for produce wealth out of waste

Friction, Abrasion and Crack Growth Behavior of In-Situ and Ex-Situ Silica Filled Rubber Composites.

Abstract: The article focuses on comparing the friction, abrasion, and crack growth behavior of two different kinds of silica-filled tire tread compounds loaded with (a) in-situ generated alkoxide silica and (b) commercial precipitated silica-filled compounds. The rubber matrix consists of solution styrene butadiene rubber polymers (SSBR). The in-situ generated particles are entirely different in filler morphology, i.e., in terms of size and physical structure, when compared to the precipitated silica. However, both types of the silicas were identified as amorphous in nature. Influence of filler morphology and surface modification of silica on the end performances of the rubbers like dynamic friction, abrasion index, and fatigue crack propagation were investigated. Compared to precipitated silica composites, in-situ derived silica composites offer better abrasion behavior and improved crack propagation with and without admixture of silane coupling agents. Silane modification, particle morphology, and crosslink density were identified as further vital parameters influencing the investigated rubber properties.