Siloxane hybrid precursors

Figure 28.3 Molecular structures of siloxane hybrid precursors. DCM= 4-dicyanomethy-lene-2-methyl-6-[p-(dimethylamino)styryl]-4/-/-pyran PBD= 2-(4-biphenylyl)-5-(4-ferf-butyl-phenyl)-1,3,4-oxadiazole NABUP= A/-(4-butyl-phenyl)-4-[(A/-2-hydroxyethyl)(methyl)amino] naphthalimide TPPy = 1,3,6,8-tetraphenylpyr-ene PHEMA= poly(2-hydroxyethyl...

The soft experimental conditions in the synthesis of P-CDAPS were optimized using experimental design. The hybrid precursor P-CDAPS has been characterized in order to determine its structure. ETIR spectra show the presence of amino groups (1564cm ) on one hand and siloxane structure (1100-1000cm ) on the other hand, conhrmed by TGA measurements. This TGA gave a Si ratio of 5.80 0.04%., conhrmed by elemental analysis. N content was determined by elemental analysis at 2.98 0.02%, which corresponds to 2.13 0.04mmol/g of amine functions, also deduced from amine titration. 

The addition of a source of molybdate anions to the hybrid precursor solution gave rise to the formation of a denser siloxane network and to a substantial increase in Tg of the organic phase. This also resulted in a large increase in the rubberyplateau modulus and in a substantial reduction in both the rate of solvent uptake and the equilibrium amount of solvent absorption. These effects are illustrated in Figures 24.8 and 24.9. 

Silicate and Hybrid Materials through Molecular Siloxanes. Renewed interest in monosilanols and si-lanediols is primarily because compounds obtained from [(ffiuO)3SiOH] and (fBuO)2Si(OH)2] serve as better singlesource precursors for ceramic materials. A number of metallasiloxanes have been synthesized starting from [(fBuO)3SiOH, and a selection of these compounds is... 

The purpose of selecting XMou-SiOj as the inorganic precursor is that they are chemically active toward siloxanes. At first the hybrid XMo,-Si02 sols were prepared via hydrolysis of TEOS in the presence of XMo,under acidic conditions. A little amount of nitric acid was added to the solution in order to increase the solubility of XMo, and still remained the mono lacunary structures. Second, the sols of the hybrid materials were introduced into the spaces between the templating PS sphere arrays (with suction applied) subsequently, a solid hybrid material skeleton was constructed via in situ sol-gel transformation. The PS templates were removed by extraction with toluene solution. 

Burkett, SL Sims, SD Mann, S Synthesis of hybrid inorganic-organic mesoporous silica by co-condensation of siloxane and organosiloxane precursors. Chem. Commun. 1996, 1367-1368. 

A new dimension in sol-gel chemistry has been opened up with sol-gel alkoxide precursors consisting of functional organic groups [R -Si(OR)3] or organic spacers directly bound to siloxanes [(RO)3Si-R -Si(OR)3j [19-21]. Figure 2 shows some examples of the precursors with trialkoxyl silanes attached to alkyl and phenyl groups. The hybrid matrices can be readily prepared by the cocondensation of these... 

A new convenient polymer modification has been developed to synthesize a series of novel silanol-containing polymers by a selective oxidation of Si—containing precursor polymers with a dimethyldioxirane solution in acetone. The silanol hydrogen bonding interactions in polymer blends as well as the silanol self-condensation to form siloxane semi-interpenetrating polymer networks in miscible polymer blends and organic-inorganic polymeric hybrids are discussed. 

Among hybrid compounds, siloxane-based materials present several advantages for the design of materials for photonics firstly, many precursors are commercially available or... 

The preparation procedure of novel ORMOCER hybrid matrix ZSUR is being pub-hshed (Reisfeld, 2004). The final solution ofZSURwas obtained from DURS (di-urethane siloxane), ESOR (epoxy-silica ormosil) and ZrOa precursor solutions. 

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