Silicon-containing polymers siloxane

Polycarbosilanes are an interesting class of polymers from a materials standpoint however, they do not occur naturally. A variety of synthetic methods can be employed to produce such polymers, but this part of the chapter will focus on using ADMET as a viable route to synthesize polycarbosilanes, siloxanes, and other silicon-containing polymers. 

Boutevin B, Guida-Pietrasanta F, Ratsimihety A (2000) Side group modified poly-siloxanes. In Silicon-Containing Polymers. Kluwer, Rotterdam, pp 79-112... 

Poly(siloxanes) and Other Silicon Containing Polymers... 

Poly(siloxanes) and other silicon containing polymers... 

Besides poly(siloxanes), a few other silicone containing polymers have been synthesized. One such polymer is poly(dimethy-1,4-silphenylene). Thermal decomposition of this polymer at 400° C in argon [3] generates methane, dimethylsilane, benzene, dimethylphenylsilane, HSi(CH3)2-C6H4-SiH(CH3)2, H(Si(CH3)2-C6H4)2-H, dimethyl-diphenylsilane, and C8H4-(Si(CH3)2-C6H4)2H. 

A vast majority of the commercially available silicon-containing polymers today are polysiloxanes or silicones. In the same way that aldehydes and alcohols are characterized by the presence of the -CHO-H and = C-OH moieties, respectively, a siloxane is a compound containing the bond =Si-0-Si=, and silicones are materials consisting of alternating silicon and oxygen atoms in which most silicon atoms are bound to at least one monofunctional organic radical. Polymers and copolymers of R, R2, and R3 monomers are termed poly(siloxanes). Linear poly(siloxanes)... 

In order to improve the solubility of aromatic polymers silicon-containing polymers have also been synthesized, by introduction of siloxane or silarylene linkages into polymer backbones such as polyamides, polybenzimidazoles and polyimides [50]. The resultant polymers show fair solubility in organic solvents but most of them have poorer thermal stability then their analogues without siloxane or silarylene linkages. 

Metathesis of 1,9-decadiene and cyclooctene with trialkoxy- and trisiloxy-substituted vinylsilanes in the presence of Grubbs catalyst, carried out in appropriate conditions, leads to the formation of bis(silyl)diene with a high yield. Similar processes performed with divinyl-substituted siloxane lead to the formation of silicon-containing polymers (via ADMET copolymerization and tandem ROM/CD polymerization), thus opening a new convenient route to synthesis of unsaturated organosilicon copolymers. 

Silicon-containing polymers, such as poly(siloxane) (3), poly(carbosilane) (4,5), and poly(silylene) (6) have found practical importance in many areas of applications, but they have been insufficiently studied in relation to their primary structure, stereoregularity, molecular weight, and higher order structure. 

Size exclusion chromatography-mass spectroscopy has been applied to structural and molecular weight studies on silicon containing polymers including hyperbranched alkoxysiloxane [30], polydimethyl siloxane [31], methyl acryloxypropyl trimethoxy silone [32] and phosphazines. 

For silicon-containing polymers, bivalent radical names replaced the source-based silane/siloxane names. For... 

Burger, C. Kreuzer, F. H. Polysiloxanes and Polymers Containing Siloxane Groups. In Silicon in Polymer Synthesis Kricheldorf, H. R., Ed. Springer Berlin, 1996 pp 113-222. 

Kawakami, Y. Imae, I. Synthesis and Characterization of Siloxane-Containing Polymers Obtained by Dehydrocoupling Polymerization. In Synthesis and Properties of Silicones and Silicone-Modified Materials Clarson, S. J., Fitzgerald, J. J., Owen, M. J., Smith, S. D., Van Dyke, M. E., Eds. ACS Symposium Series 838 American Chemical Society Washington, DC, 2003 pp 61-71. 

The selective dense layer of hydrophilic membranes is made from different polymers with a high affinity for water. These polymers contain ions, oxygen functions like hydroxyl, ester, ether or carboxylic moieties, or nitrogen as imino or imi-do groups. Preferred hydropilic polymers are polyvinylalcohol (PVA) [32], poly-imides, cellulose acetate (CA) or natural polymers like chitosan [33] or alginates. Organophilic membranes usually consist of crosslinked silicones, mostly polydimethyl siloxane (PDMS) or polymethyl octyl siloxane (POMS). 

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