Carbohydrates polysiloxanes

Main-Chain Carbohydrate-Polysiloxane Block Copolymers... 

An original approach for combining polysiloxanes and sugars has been reported by Thiem et al. [32] and Domschke et al. [33], with the preparation of main-chain carbohydrate-polysiloxane copolymers. In these structures, the sugar units are... 

Keywords Carbohydrate sugar glyco polysiloxane glycopolysiloxane hydrosilylation polymer glycopolymer... 

In this article, we reviewed the different ways described to date for the synthesis of well-defined glycosilicones or glycopolysiloxanes . They have been called also carbohydrate (-grafted, -functional, -modified) polysiloxanes , sugar (-grafted... etc) polysiloxanes , or sweet polysiloxanes . We focussed on the advantages and drawbacks of each method. 

Stadler et al. has synthesized several sugar-grafted polysiloxanes obtained by multistep procedures, including the preparation of the protected allyl-functionalized-sugars, the hydrosilylation with a statistical poly(dimethyl-co-hydrogenomethyl)-siloxane and finally the removal of the carbohydrate protective groups. 

Further physicochemical characterizations were made on both the protected and deprotected carbohydrate-grafted polysiloxanes in a later publication [14]. Size Exclusion Chromatography (SEC), viscosimetric and static light scattering... 

G. Jonas, R. Stadler, Acta Polymer., 1994, 45, 14-20. Carbohydrate modified polysiloxanes II. Synthesis via hydrosUation of mono-, di-and oligosaccharide aUylglycosides . 

K. Loos, G. Jonas, R. Stadler, Macromol. Chem. Phys. 2001,202,3210-3218, Carbohydrate Modified Polysiloxanes, 3. Solution Properties of carbohydrate-PolysUoxane conjugates in Toluene . 

Mechanistic considerations (e.g., the extensive work published on brush-type phases) or the practitioner s experience might help to select a chiral stationary phase (CSP) for initial work. Scouting for the best CSP/mobile phase combination can be automated by using automated solvent and column switching. More than 100 different CSPs have been reported in the literature to date. Stationary phases for chiral pSFC have been prepared from the chiral pool by modifying small molecules, like amino acids or alkaloids, by the deriva-tization of polymers such as carbohydrates, or by bonding of macrocycles. Also, synthetic selectors such as the brush-type ( Pirkle ) phases, helical poly(meth) acrylates, polysiloxanes and polysiloxane copolymers, and chiral selectors physically coated onto graphite surfaces have been used as stationary phases. 

LOO Loos, K., Jonas, G., and Stadler, R., Carbohydrate modified polysiloxanes. 3. 

Scheme 5. A commercially available carbohydrate-modified polysiloxane (Wacker Belsil SPG-128VP) Caprylyl Dimethicone Ethoxy Glucoside, 20% in cyclopentasiloxane (D5)) [80]...

High molecular weight polysiloxanes modified with mono-, di- or oligosaccharides showed different aggregation behavior in solution, depending on the detailed chemical structure of the carbohydrate moiety and its stereochemistry [88],... 

The same authors prepared a sales of allyl-group-containing bifunctional carbohydrate derivatives that were reacted with hydrodimethylsUyl-taminated polysiloxane using Speier s catalyst [132]. 

The preparation of polymeric materials from renewable resources is of great economic and ecological significance. Oils and fats are one of the most important renewable materials since they offer a large number of possibilities for application that can be rarely met by petrochemistry. Although the hydrosilylation of olefins has been widely studied, a few reports have appeared on the fatty acid esters (4). Carbohydrate-modified polysiloxanes are another very important group of hybrid materials. Some examples of such modified, comb-structured polysiloxanes and also a few examples of carbohydrate-segmented polydimethylsiloxane block copolymers have been described. Hydrosilylation has also been used for the synthesis of silylated polycarbonates or polycarbonate-disiloxane-polycarbonate triblock copolymers. 

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