Comparative study of the surface hydroxyl groups of fumed and precipitated silicas. 3. DRIFT characterization of grafted n-hexadecyl chains

Langmuir ◽  
1990 ◽  
Vol 6 (8) ◽  
pp. 1389-1395 ◽  
Author(s):  
A. Burneau ◽  
O. Barres ◽  
A. Vidal ◽  
H. Balard ◽  
G. Ligner ◽  
...  
1986 ◽  
Vol 1 (1) ◽  
pp. 114-119
Author(s):  
M. Bretz ◽  
A. G. Shastri ◽  
J. Schwank

A promising method for the preparation of sizeable quantities of structurally well-defined, highpurity MgO powder is reported. The morphology and surface uniformity of the powder is comparable to that of MgO smokes but with narrow size distribution of particles. Sample characterization of these oxide powders is accomplished by combining structural TEM/STEM examination with krypton gas adsorption isotherms. The latter technique is sensitive to the presence of surface hydroxyl groups and of surface roughness on an atomic scale. Highresolution TEM indicates a perfect cubic morphology, intra-crystallite orientation, and dendritic sintering of cubes. In the STEM mode sharp convergent beam electron diffraction patterns are obtained, and in thick specimen regions Kikuchi lines appear, indicating the absence of crystal defects. After prolonged outgassing to remove surface hydroxyl groups, a krypton adsorption isotherm contains a near vertical submonolayer riser and second layer step along with partial wetting features near saturation. These near-ideal dendritic ceramic powders, therefore, provide a research bridge between single crystal surface studies and large-scale powder technology.


Langmuir ◽  
1989 ◽  
Vol 5 (2) ◽  
pp. 447-451 ◽  
Author(s):  
M. Zaborski ◽  
A. Vidal ◽  
G. Ligner ◽  
H. Balard ◽  
E. Papirer ◽  
...  

2012 ◽  
Vol 512-515 ◽  
pp. 2443-2447 ◽  
Author(s):  
Li Ying Guo

Multiplayer core-shell TiO2/PSt/PVP hybrid microspheres were successfully synthesized by the copolymerization of vinylpyrrolidone in the solution of ethyl acetate with TiO2/PSt core-shell hybrid microspheres which were formed through the encapsulation of KH570-g-TiO2 sol particles with styrene, while the active KH570-g-TiO2 sol particles were prepared by the hydrolysis condensation of KH-570 with tetrabutyl titanate. Characterization technologies of FT-IR and TGA were applied to investigate the structure and the thermal stability of the product. The results showed that the hydroxyl groups from the hydrolysis of KH-570 condensed with the surface hydroxyl groups of TiO2, as well as PSt and PVP were grafted successively onto the surface of KH570-g-TiO2 sol particles. The thermal decomposition temperature of TiO2/PSt/PVP was higher than TiO2/PSt, which also indicated that the obtained product was the final objective product.


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