نتایج جستجو برای: hydrophobic fumed silica

تعداد نتایج: 69443  

1998
Srinivasa R. Raghavan Michael W. Riley Peter S. Fedkiw Saad A. Khan

Dynamic rheological techniques are used to probe the microstructures present in fumed silica-based composite polymer electrolytes. These electrolytes are obtained by dispersing hydrophobic fumed silica in a poly(ethylene glycol)-lithium salt solution and display high conductivities (σ298K > 10-3 S/cm), mechanical stability, and easy processability. The materials behave as soft solids (gels) und...

Journal: :Journal of the American Chemical Society 2012
Haiyuan Zhang Darren R Dunphy Xingmao Jiang Huan Meng Bingbing Sun Derrick Tarn Min Xue Xiang Wang Sijie Lin Zhaoxia Ji Ruibin Li Fred L Garcia Jing Yang Martin L Kirk Tian Xia Jeffrey I Zink Andre Nel C Jeffrey Brinker

We have developed structure/toxicity relationships for amorphous silica nanoparticles (NPs) synthesized through low-temperature colloidal (e.g., Stöber silica) or high-temperature pyrolysis (e.g., fumed silica) routes. Through combined spectroscopic and physical analyses, we have determined the state of aggregation, hydroxyl concentration, relative proportion of strained and unstrained siloxane...

Journal: :journal of chemical and petroleum engineering 0
atieh eskandari faculty of chemical, petroleum and gas engineering, semnan university, semnan, i.r. iran. mansoor anbia research laboratory of nanoporous materials, faculty of chemistry, iran university of science and technology, tehran 16846-13114, iran. mansour jahangiri faculty of chemical, petroleum and gas engineering, semnan university, semnan, i.r. iran. fariba mohammadi nejati faculty of chemical, petroleum and gas engineering, semnan university, semnan, i.r. iran.

silicon and aluminum sources are most important reactants in the synthesis of zeolite. the use of the silicon source has an important effect on the crystallization of zeolites. also, it can change the properties of the end product. this work reports the influence of three common commercial silica sources such as colloidal silica (ludox am-30), fumed silica and water glass on the crystallinity o...

Silicon and aluminum sources are most important reactants in the synthesis of zeolite. The use of the silicon source has an important effect on the crystallization of zeolites. Also, it can change the properties of the end product. This work reports the influence of three common commercial silica sources such as colloidal silica (Ludox AM-30), fumed silica and water glass on the crystallinity o...

Journal: :Polymers 2023

Hydrophobic fumed silica (HFS) is a commonly used rheology additive in waterborne coatings. A series of experiments were conducted on the HFS-dispersing technology this study. The size and structure HFS primary particles observed via transmission electron microscopy (TEM). measurement results TEM D50 = 13.6 nm D90 19.7 nm, respectively. particle dispersion performance tested dynamic light scatt...

2003
H. J. Walls Peter S. Fedkiw Thomas A. Zawodzinski Saad A. Khan

The ion-transport properties of composite electrolytes composed of oligomers of poly~ethylene glycol! dimethyl ether, hydrophobic fumed silica, and Li~CF3SO2)2N ~LiTFSI! are investigated using nuclear magnetic resonance ~NMR!, electrophoretic NMR ~ENMR!, ac impedance spectroscopy, and rheology. The effects of fumed silica and salt concentration on ionic conductivity, diffusivity of ions and oli...

2000
Srinivasa R. Raghavan Jun Hou Gregory L. Baker Saad A. Khan

Colloidal interactions between particles dispersed in a liquid can be suitably tailored by modifying the surface chemistry of the particles. In the case of fumed silica particles, the surface can be systematically altered from hydrophilic to hydrophobic by replacing a portion of the original silanol (Si-OH) groups by nonpolar alkyl chains. In this study, we probe the effect of surface modificat...

2008
David Jesson D. A. Jesson A. Arkhireeva

The adsorption of polyester onto organically modified silicas (ormosils) and (commercial) fumed silica has been compared utilising ToF-SIMS. The thermodynamics of each system was examined by constructing adsorption isotherm plots which indicated that the adsorption of polyester onto one of the modified silicas used may be a two stage process. Adsorption onto the fumed silica is in accord with t...

2005
Susmit Basu Himadri Paul Chinnakonda S. Gopinath Sumit Bhaduri Goutam Kumar Lahiri

Anionic platinum carbonyl cluster has been ion paired with cinchonidium groups that are chemically bound to the surface of MCM-41 and fumed silica. In the hydrogenation of methyl pyruvate or acetophenone the fumed silica-based catalyst gives zero enantioselectivity, but under optimum conditions enantiomeric excesses of > 90 and ∼ 40%, respectively, are obtained with the MCM-41-based catalyst.

Journal: :RESOURCES PROCESSING 1991

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