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Precipitated silica

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


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Journal ArticleDOI
TL;DR: In this paper, the effects of mixing temperature and mixing time on the reaction of 3-octanoylthio-1-propyltriethoxysilane (NXT silane) during mixing with precipitated silica and natural rubber (NR) were investigated.
Abstract: The effects of mixing temperature and mixing time on the reaction of 3-octanoylthio-1-propyltriethoxysilane (NXT silane) during mixing with precipitated silica and natural rubber (NR) were investigated. Results showed that the reaction between NXT silane and precipitated silica can proceed at temperatures above 130°C. Because of the blocking group of NXT silane, the silane–NR coupling reactivity is low, so that the reaction of NXT silane with NR occurs only during the curing period. There is no reaction between NXT silane and NR during mixing, which showed that the mixing time of silica-filled NR compound containing NXT silane must be longer than 10 min at 150°C to obtain the desired silane coupling efficiency. With increasing mill temperature, the coupling efficiency increases. A high mixing temperature promotes improvement of silane–silica coupling efficiency, although the tensile strength, 100% modulus, 300% modulus, and hardness of NR vulcanizates decrease. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2295–2301, 2004

13 citations

Journal ArticleDOI
TL;DR: In this article, the properties of precipitated silica modified with hexadecylamine, dodecanol, 9decen-1-ol and γ-mercaptopropyltrimethoxysilane have been characterised and related to elastomer reinforcement capability.
Abstract: The properties of precipitated silica modified with hexadecylamine, dodecanol, 9-decen-1-ol and γ-mercaptopropyltrimethoxysilane have been characterised and related to elastomer reinforcement capability. Extensive modification with these agents decreased the specific surface area and the critical surface energy of silica, rendering filler with a reduced tendency to agglomerate. These changes in silica surface properties facilitated filler incorporation and dispersion in a tyre rubber compound, but diminished its reinforcement capacity as measured by bound rubber and stress-strain analysis. The data suggest that losses in surface energy support filler dispersion by reducing silica agglomeration, but reduce reinforcement capacity by weakening adhesion between filler and elastomer. However, optimisation of the extent of silica modification is feasible, given that the decline of silica agglomeration with respect to surface energy is more intense than the loss of elastomer reinforcement potential.

13 citations

Journal ArticleDOI
TL;DR: In this article, a ternary SiO 2 :CTAOH:H 2 O system was used to synthesize Si-MCM-48 mesoporous molecular sieves.
Abstract: The hydrothermal synthesis of Si-MCM-48 mesoporous molecular sieves was carried out using a ternary SiO 2 :CTAOH:H 2 O system wherein differently manufactured amorphous silica powders such as fumed silica (FMDS), spray dried precipitated silica (SDPS) and flash dried precipitated silica (FDPS) were used as silica source materials. The changes in structural/textural properties were evaluated using powder XRD, N 2 adsorption–desorption and scanning electron microscopy techniques. Studies on the progressive development of MCM-48 mesophases revealed that, the reactivity of the silica source follow the trend: FMDS > SDPS > FDPS. MCM-48 synthesized using low cost FDPS has exhibited thicker pore walls but poorer orderness, while MCM-48 prepared from relatively expensive FMDS has thinner pore walls and more ordered structure. Moreover, the extent of contraction caused by calcinations, agglomerate size and structural stability were found to depend on the reactivity of the silica source used.

13 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the kinetics of the partial oxidation of methane to formaldehyde (MPO) on a precipitated silica catalyst in the 500-800°C range.
Abstract: The kinetics of the partial oxidation of methane to formaldehyde (MPO) on a precipitated silica catalyst in the 500-800°C range was investigated. The influence of temperature and reaction mixture composition on the density of reduced sites of the catalyst under steady state was evaluated by in situ reaction temperature oxygen chemisorption measurements. The kinetics of the MPO on silica is pseudo first and zero-order on P CH4 and P O2 , respectively, while the density of reduced sites depends upon the square root of the P CH4 /P O2 ratio. The rate-determining step is the activation of C-H bond of CH 4 molecules (E red =142 kJ/mol), while oxygen replenishment is a nonactivated reaction step (E ox ≃20 kJ/mol). A Langmuir-Hinshelwood kinetic model, accounting for a two-site-dissociative activation mechanism of both CH 4 and O 2 , thoroughly describes the steady state of the silica surface and the reaction kinetics of the MPO in the 500-800°C range.

13 citations

Patent
13 Apr 2001
TL;DR: In this paper, a mixture of at least one filler and organosilicon compounds of the general formula Y-S x -Z, wherein the filler is surface-treated, hydrophobic, precipitated silica, are prepared by homogeneously applying an organosaicon compound from a nozzle to the surface-treated, hydrastic, and precipitated, silica in a mixing unit at a temperature less than 50°C.
Abstract: Mixture of at least one filler and organosilicon compounds of the general formula Y—S x -Z, wherein the filler is surface-treated, hydrophobic, precipitated silica, are prepared by homogeneously applying an organosilicon compound from a nozzle to the surface-treated, hydrophobic, precipitated silica in a mixing unit at a temperature of less than 50° C. The mixture can be used in rubber mixtures.

13 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20236
202217
202118
202030
201931
201841