Structure-Related Mechanical Properties of Ormosils by SOL-GEL Process

1992 ◽  
Vol 271 ◽  
Author(s):  
Yi Hu ◽  
John D. Mackenzie

ABSTRACTThe mechanical properties corresponding to the different structures of organically modified silicates (Ormosils) prepared by the sol-gel process were studied. Tetraethoxysilane (TEOS) and polydimethyl siloxane (PDMS) were used as the inorganic and polymeric components, respectively. Large variations in the microstructure of the Ormosils were found by changing the reaction temperature, and the content of PDMS, acid catalyst (HCI),and water. The structure of the Ormosils and the mechanical properties were correlated by the edge connectivity. Modulus of elasticity and fracture strength were used to study their relations Ormosils structures.

2007 ◽  
Vol 336-338 ◽  
pp. 574-576
Author(s):  
Hua Rong ◽  
Chun Fang Ye ◽  
Yu Yang ◽  
Guo Dong Qian ◽  
Zhi Yu Wang ◽  
...  

Laser dyes perylene red (p-red) or pyrromethene 567 (p567) were co-doped with coumarin 440 (C440) or coumarin 500 (C500) into MTES- and VTES-derived organically modified silicates (ORMOSILs) by sol-gel process. The effects of coumarin dye concentration on the laser performances of p-red and p567 were investigated. The results from laser efficiency measurements illustrated that at optimized coumarin concentration, the slope efficiency of co-doped p-red increased by a factor of 2 while that of co-doped p567 increased marginally. It was also found that by co-doping coumarin, the laser wavelength of p-red blue shifted and the laser thresholds for p567 and p-red could be reduced. The energy transfer mechanisms involved were also discussed.


1984 ◽  
Vol 32 ◽  
Author(s):  
H. Schmidt

ABSTRACTThe introduction of organic groups into inorganic networks by the sol-gel process opens the possibility for the preparation of new materials, and typical properties resulting from inorganic as well as from organic components may be combined. Some general aspects and different examples of material developments are reviewed.


1986 ◽  
Vol 73 ◽  
Author(s):  
H. Schmidt ◽  
B. Seiferling

ABSTRACTThe combination of inorganic polymeric networks with organic components leads to inorganic-organic polymers. A convenient method for the introduction of organic radials into an inorganic backbone is the use of organosubstituted silico esters in a polycondensation process. This leads to≡Si-O-Si≡ network containing materials, so-called organically modified silicates (ORMOSILs). For the synthesis of the inorganic backbone, in opposition to the high temperature preparation of non-metallic inorganic materials like ceramics, “soft chemistry” methods have to be applied in order to preserve organic groupings to be incorporated. Therefore, the sol-gel process is a suitable technique [1–5]. A review over basic synthesis principles and chemical methods, their effect on special material properties and the application potential will be given.


1990 ◽  
Vol 180 ◽  
Author(s):  
Young J. Chung ◽  
Su-Jen Ting ◽  
John D. Mackenzie

ABSTRACTA new technique which permits the successful preparation of ORMOSILS (Organically Modified Silicates) with rubbery elasticity has been developed. Common alkoxides were reacted with polydimethyl siloxane (PDMS) and the microstructures were carefully controlled. Large monoliths of the porous rubbery ORMOSILS have been prepared. Gelation process was studied by 29Si liquid NMR spectroscopy. A structural model for rubber elasticity of ORMOSILS was proposed.


2016 ◽  
Vol 697 ◽  
pp. 293-296
Author(s):  
Xiao Yang Zhang ◽  
Xi Wei Qi ◽  
Zhi Yuan Yang ◽  
Li Bao ◽  
Min Zhang

Hydrothermal method and sol-gel process were used to synthesize multiferroic BiFeO3 ceramics. X-ray diffraction, scanning electron microscopy, vickers diamond indenter and three-point bending method were used to investigate the effects of methods on the phase structure, microstructures and mechanical properties. Cold isostatic pressing on the ceramics with two different loads (10 MPa, 200 MPa) was used to illustrate the influence of pressure in mechanical properties. The results show that all samples are crystallized in the perovskite phase. A few small traces of impurity are observed at a 2θ of ~28 o, which are found to be those of Bi2Fe4O9. The SEM images depict that samples prepared by sol-gel process are more uniform and the grain size is slightly larger than that of hydrothermal processed samples. The investigations on the hardness and flexural strength demonstrate the ceramics prepared by hydrothermal method have better mechanical properties than that of sol-gel process, and the mechanical properties can be obviously enhanced by increasing pressure.


RSC Advances ◽  
2016 ◽  
Vol 6 (13) ◽  
pp. 10736-10742 ◽  
Author(s):  
Berta Domènech ◽  
Ignasi Mata ◽  
Elies Molins

A new epoxy–silica porous material prepared via one-pot sol–gel process. Mechanical properties can be continuously tuned by modifying reactant proportions.


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