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Organosiloxanes, synthesis

Sokolov N.N., Methods of Poly(organosiloxane) Synthesis, Moscow -Leningrad, Gosnergoizdat, 1959, p. 103. (Rus)... [Pg.258]

In this section of our review, recent developments in the synthesis of organosiloxane containing multiphase copolymers and networks will be discussed. Basic structural and physical characteristics of the copolymers (e.g. spectroscopic, thermal, molecular weight, etc.), supporting the formation of the multiphase structures will be given. Mechanical and morphological characteristics of representative systems will be discussed in Chapt. 4. [Pg.28]

Besides their unique combination of properties, another important factor that makes organosiloxanes so attractive in the synthesis of block copolymers, is the ease of... [Pg.75]

A new route to alkyl silicates and organosiloxanes is described. This route has three steps. These are (1) the protonation of a silicate (obtained by collection, mining, or laboratory or commercial synthesis), (2) the esterification of the silicic acid formed by the protonation, and (3) the organodealkoxylation of the alkyl silicate resulting from the esterification. An important feature of this route is that it does not depend on elemental silicon. The route is illustrated with the synthesis of (EtO)4Si from 7-Ca2SiC>4,... [Pg.238]

Belorgey, G. Sauvet, G. Organosiloxane Block and Graft Copolymers. In Silicon-Containing Polymers. The Science and Technology of Their Synthesis and Applications Jones, R G., Ando, W., Chojnowski, J., Eds. Kluwer Dordrecht, 2000 Chapter 2, pp 43-78. [Pg.688]

As it is well known, the (Si-0) bond in organosiloxanes may be considered to be polar or partially ( 50%) ionic.(12) Therefore, it can be cleaved by the attack of strong acids or bases. This is the main rationale behind the "equilibration" route to the synthesis of a wide variety of functionally terminated siloxane oligomers(12-14) from cyclic siloxanes and a.ordifunctional disiloxanes as shown in Scheme 3. [Pg.164]

Organically modified MCM-41 can be prepared directly by using alkoxysilanes or organosiloxanes in the synthesis mixture thus coating the internal wall of the pores with functional groups. An example of a condensation reaction of an alcohol with the surface silanol groups to modify the pore wall is shown in Figure 7.22. [Pg.332]

Starting in the 1950s a process was developed that leads from small-molecule silicon alkoxides such as tetraethoxysilane (tetraethyl orthosilicate), to organosiloxane oligomers and low polymers, and eventually to silica via a low temperature synthesis route.14 24 A simplified outline of the basic chemistry is shown in reactions (l)-(4), where R is an ethyl or higher alkyl unit. Any or all of the Si-OR bonds can be... [Pg.313]

Tris(y-trifluoropropyl)chlorosilane is a parent monomer in the synthesis of high-temperature a,co-tris(y-trifluoropropylsiloxy)organosiloxane liquids. [Pg.23]

Thus, synthesis of cyclolinear organosiloxane and carbosiloxane copolymers with monocyclic frag-ments in the backbone, obtained in HFC, hydride polyaddition and polymerization reactions, are considered in this review. The above-shown data on high-molecular polymers with regular dispo-sition of cyclic fragment in the backbone are mainly synthesized by HFC and hydride polyaddition reactions. As for polymerization of bicyclosiloxanes, they are almost useless for high polymer syn-thesis. [Pg.257]

In contrast, the synthesis of the initiator functionality and the modification of the poIy(siloxane) is only one single step for TMP using an easily available diazonium compound 2 with a yield of about 60-80 %. Structure verification and determination of the initiator group content could be done by h NMR spectroscopy. GPC analysis showed that the modified poly(organosiloxane)s retain their original molecular weights. About 4-8 initiating sites have been attached onto the silicone backbone. Due to the chromophores, AMP and TMP are yellow products. [Pg.661]

Polymeric initiators based on azo or triazene modified poly(organosiloxane)s can be used to synthesize graft copolymers with silicone backbone and thermoplastic side chains. The azo functionality has some advantages such as lower thermal stability, known reaction mechanism, no homopolymer formation and cleaner graft products. However, the synthesis of the triazene polymeric initiators requires fewer synthetic steps. The graft products microseparate but form stable films. [Pg.663]

Scheme 2. Synthesis and characterization of precrosslinked poly(organosiloxane) particles... Scheme 2. Synthesis and characterization of precrosslinked poly(organosiloxane) particles...
In contrast to the hydrolysis technology, the methanolysis process allows for the one-step synthesis of organosiloxane oHgomers and methyl chloride without formation of hydrochloric acid (64,65). The continuous methanolysis can also yield quantitatively linear silanol-stopped oligomers by recycle of the cycHc fraction into the hydrolysis loop. [Pg.45]

Ellis, S. R. M. 1971. Vapor phase extraction process. Br. Chem. Eng. 16 358. Elsbernd, C. S. 1988. Synthesis, kinetics, and supercritical fluid fractionation studies of functional organosiloxanes and their incorporation into segmented copolymers. Ph.D. diss., Virginia Polytechnic Institute and State University. [Pg.524]

Elsbernd, C. S., M. Spinu, V. J. Krukonis, P. M. Gallagher, D. K. Mohanty, and J. E. McGrath. 1990a. Synthesis and fractionation studies of functionalized organosiloxanes. In Silicon-based polymer science, ed. J. M. Zeigler and F. W. G. Fearon, 145. Advances in Chemistry Series No. 224. Washington, D.C. American Chemical Society. [Pg.524]

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. [Pg.115]

The synthesis of a further class of polymers with cyclopentadienylirondicarbonyl dimer units in the backbone has been described.These materials possess organosiloxane spacers and were prepared via condensation reactions that are illustrated for the case of 220 (Equation (82)). [Pg.387]

The main reason for the investigation was to create convenient methods for the synthesis of organosiloxane copolymers with monocyclosiloxane fragments in the side chain. To establish the influence of the cyclic fragment on the properties of copolymers the initial difunctional organodichlorosiloxyorganocyclosiloxanes and a new class of cyclolinear copolymers, with monocyclic fragments in the side chain were synthesised. [Pg.142]

Synthesis of Organosiloxane Copolymers with Monocyclic Fragments in the Side Chain... [Pg.151]


See other pages where Organosiloxanes, synthesis is mentioned: [Pg.30]    [Pg.57]    [Pg.63]    [Pg.180]    [Pg.185]    [Pg.240]    [Pg.656]    [Pg.680]    [Pg.284]    [Pg.617]    [Pg.100]    [Pg.3]    [Pg.49]    [Pg.60]    [Pg.168]    [Pg.169]    [Pg.660]    [Pg.660]    [Pg.145]    [Pg.508]    [Pg.1832]    [Pg.304]    [Pg.281]    [Pg.471]    [Pg.151]   


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