On-Line Spectroscopic Studies of Group IV Alkoxides and their Interactions with Organic Additives During the Sol-Gel Process

1996 ◽  
Vol 435 ◽  
Author(s):  
D. Wettling ◽  
S. Truchet ◽  
J. Guilment ◽  
O. Poncelet
1998 ◽  
Vol 519 ◽  
Author(s):  
R. Cinier ◽  
J. Guilment ◽  
O. Poncelet ◽  
S. Truchet ◽  
D. Wettling

AbstractThe monitoring of different reactions such as the stabilization of the alkoxides with polymerizable organic additives, the building of the inorganic network during the hydrolysis process, and in a same manner, the polymerization of the organic additives, can be of great importance for the development of hybrid materials with improved processability.NIR spectroscopy is a very versatile technique but lacks of specificity. IR and Raman give more interpretative results but are not always easy to run on a process. We used both techniques along with chemometric tools to extract relevant information from our processes. Then 2D correlation allowed to benefit from the specificity of IR and Raman to develop robust NIR methods able to be used on line to control the different steps of the sol-gel process.The hydrolysis of mixed species of titanium containing chloro, isopropoxo and methacrylato ligands will be discussed in terms of mechanism occuring during the sol-gel process.


1994 ◽  
Vol 346 ◽  
Author(s):  
F. Akbarian ◽  
B. Dunnt ◽  
P.D. Fuquat ◽  
J. Mckiernan ◽  
E. Simoni ◽  
...  

ABSTRACTThe synthesis of sol-gel glasses containing organic and organometallic molecular dopants has been well established as an approach for creating new optical materials. Some of these properties are dependent upon chemical reactions which occur in porous xerogel matrices during the sol-gel process or when encapsulated molecules are exposed to other molecules in solution. In this paper, the study of two different types of chemical reactions in the pores of xerogel matrices is reported. In one case copper phthalocyanine is used to characterize dimerization within the pores. The results show that dimer formation is most likely to occur towards the end of the drying stage as the dye concentration in the pores increases from solvent evaporation. A second example involves the use of a pump-probe technique to determine the rate of proton recombination inside the pores of silica monoliths. The behavior of sols and gels is similar to aqueous solution while recombination of protons in the xerogel seems to be affected by the walls of the pores.


1992 ◽  
Vol 271 ◽  
Author(s):  
O. Poncelet ◽  
J -C. Robert ◽  
J. Guilment

ABSTRACTOrganic additives are commonly used in sol-gel chemistry [1]. They can operate as stabilizers of reactive metal alkoxides [2] towards hydrolysis or as drying control chemical additives (such as dimethylformamide). These organic compounds and the by-products of sol-gel reactions can drastically modify the physical properties of final oxide materials, so that it is necessary to optimize the use of these additives. The first steps of hydrolysis of metal alkoxides stabilized by organic additives have been studied by many sophisticated analytical techniques which are difficult to use at technical level and often strongly alter the sol-gel reactions [3]. We chose to use FT-Raman and Infrared spectrocopies, which allow to remain as close as possible of the sol-gel process without altering it. The first steps of hydrolysis of group (IVb) metal alkoxides, more particularly titanium, modified by chlorides, carboxylic acids and alkanolamines have been investigated.


2015 ◽  
Vol 476 ◽  
pp. 432-441 ◽  
Author(s):  
Yuanyuan Cai ◽  
Yi Wang ◽  
Xianfu Chen ◽  
Minghui Qiu ◽  
Yiqun Fan

2005 ◽  
Vol 17 (3) ◽  
pp. 231-238 ◽  
Author(s):  
Zilin Chen ◽  
Katsuyoshi Hayashi ◽  
Yuzuru Iwasaki ◽  
Ryoji Kurita ◽  
Osamu Niwa ◽  
...  

2002 ◽  
Vol 4 (19) ◽  
pp. 4830-4837 ◽  
Author(s):  
Miyuki Yabuki ◽  
Ryoji Takahashi ◽  
Satoshi Sato ◽  
Toshiaki Sodesawa ◽  
Katsuyuki Ogura

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