Precipitated silica

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

Tire having carcass ply and/or circumferential carcass belt reinforced by silica and made of rubber composition rich in natural rubber and rich in reinforcing agent of silica

Abstract: PROBLEM TO BE SOLVED: To provide a tire having a diene-based rubber composition rich in natural rubber and composed of components of carcass plies and/or circumferential carcass belts. SOLUTION: In this tire composed of cords of the belt and carcass which are each coated with the rubber composition rich in the natural rubber, wherein the rubber composition contains natural cis-1,4-polyisoprene rubber in an amount of 80-100 phr and cis-1,4-polybutadinene rubber in an amount of 0-20 phr, a rubber composition for the plies of the carcass contains (A) precipitated silica agglomerates in an amount of 30-60 phr and carbon black for reinforcing the rubber in an amount of 1-10 phr and (B) a coupling agent for the silica, and another rubber composition for plies of the belt contains (A) a reinforcing agent of carbon black in an amount of 30-60 phr and the precipitated silica in an amount of ≤10 phr, or (B) the precipitated silica agglomerates in an amount of 30-60 phr, the carbon black for reinforcing the rubber in an amount of 1-10 phr, and the coupling agent for the silica. COPYRIGHT: (C)2003,JPO

Influence of TESPT on the Pysico-Mechanical and Dielectric Properties of Silica Filled SBR Composites

Abstract: Bis (3-triethoxysilylpropl) tetrasulfide (TEPST) was found to affect the curing characteristics, physico-mechanical, and dielectric properties of styrene butadiene rubber (SBR) samples filled with precipitated silica. The dielectric properties of these samples were studied by means of broadband Ac relaxation spectroscopy in the frequency range between 0.01 Hz to 1 MHz Hz and at different temperatures. The values of e' and e" decreased with the increase ofthe silane content. This could be due to the reduction in the number of silanol group which are highly polar by TEPST. The α―relaxation associated with glass-rubber transition shifts to lower frequencies at constant temperature as silane content reaches a value of 8 phr. In addition this investigation showed that bound rubber, cyclic fatigue life and tensile strength were optimized when 8 phr TEPST was added.

Tear Strengths of Poly(Dimethylsiloxane) Networks Reinforced with in-Situ Precipitated Silica

Abstract: The tear strengths of in-situ filled poly(dimethylsiloxane) (PDMS) networks were investigated using “trouser-tear” tests. The filled PDMS networks were prepared by the simultaneous curing and in-situ precipitation technique, the silica reinforcing phase being obtained by the hydrolysis and condensation of tetraethoxysilane present in excess of that required for the chain end-linking process. Transmission electron micrographs showed well-dispersed and unagglomerated silica particles, and thermogravimetric analysis indicated that the silica particles gave some improvements in thermal stability. In the tearing tests, “stick-slip” tearing was observed at higher rates, especially for the filled networks. The tear strengths were found to increase with increase in the amount of silica incorporated, with the largest increases occurring at the low silica contents.

Microporous material exhibiting low alkali metal content

Abstract: Microporous material comprising water insoluble thermoplastic organic polymer and particulate amorphous precipitated silica not only exhibits low particulate emissions during handling and use, but also has a low extactable alkali metal content. Microporous material having these characteristics is especially useful in clean rooms where electronic devices such as integrated circuits are manufactured. Such microporous material may be produced by employing amorphous precipitated silica particles having low alkali metal content as all or a substantial proportion of the amorphous precipitated silica particles constituting the microporous material.

Improving Flow Property of Nifedipine Loaded Solid-Lipid Nanoparticles by Means of Silica for Oral Solid Dosage Form

Abstract: In this study, a new formulation of silica nanocomposite containing nifedipine (NI) loaded freeze-dried solid-lipid nanoparticles (NI-SLNs) and silica have been developed with improved flowability of powders, which can lead to the formulation of a widely acceptable oral dosage form. The stable NI-SLNs were prepared using two phospholipids, hydrogenated soybean phosphatidylcholine and dipalmitoylphosphatidylglycerol mixed with 2.5% w/v trehalose as a cryoprotectant followed by lyophilization. We employed various grades of two types of silica, such as fumed and precipitated. Silica improved the poor flow property of NI-SLNs to good category as per USP-29. In addition, most of the silica nanocomposites showed the satisfactory results in their physicochemical properties such as particle size, polydispersity index, zeta potential, and recovered potency by around 100 nm, 0.3, -50 mV, and 80%, respectively. Furthermore, it was found that NI-SLNs were easily released form nanocomposites within 30 min, therefore, suggesting an improvement of drug dissolutions. Among them, precipitated silica cooperated fairly in improving the powder characteristics as well as the physicochemical, morphological, and pharmaceutical properties.