Polysiloxane synthesis

Chiral Organofunctional Polysiloxanes Synthesis, Properties, and Applications... 

Zhou, Y. et al., Efficient catalysis of polysiloxane synthesis by silicatein a requires specific hydroxy and imidazole functionalities, Angew. Chem. Int. Ed., 38, 780, 1999. 

Condensation reactions of silanols provides another method for polysiloxane synthesis. Hydroxy-terminated siloxane oligomers or polymers can be further condensed to polymers of higher molecular weight by condensation with loss of water (equation 23). This reaction is catalyzed by various metal salts tin salts have been widely used. Mixtures of two different a, co-dihydroxysiloxane oligomers may be condensed to give block copolymers. 

Fig. 6. Suggested reaction mechanism for silicatein-mediated catalysis of polysiloxane synthesis from silicon ethoxides at neutral pH. The mechanism suggested is closely analogous to that known for the structurally similar proteolytic enzymes explanation in text. Reprinted from [7],...

Silicon Biotechnology Proteins, Genes and Molecular Mechanisms Controlling Biosilica Nanofabrication Offer New Routes to Polysiloxane Synthesis.5... 

Cypryk, M., General Review of Polysiloxane Synthesis. In Silicon-Based Inorganic Polymers, De Jaeger, R. Gleria, M., Eds. Nova Science New York, 2008 pp 1-59. 

Benouargha, A. Boutevin, B. Caporiccio, G. Essassi, E. Guida-Pietrasanta, F. Ratsimihety, A., Hybrid Silalkylene Polysiloxanes Synthesis and Thermal Properties. Eur. Polym. J. 1997,33,1117-1124. 

Aldehyde-Functional Polysiloxane Synthesis. Poly (dimethylsiloxanes) containing 1-hexenyl-dimethylsiloxane end groups, DC 7691 (n = 200), DC 7692 (n = 100) and DC 7697 (n = 30), were dissolved in hexane or methylene chloride (1 g/ml) and the solutions were cooled to -20°C. Ozone was then bubbled through the solutions and then into a Nal solution to decompose any excess that had not been reacted and prevent its release to the atmosphere. Treatment of the reaction mixtures with ozone was stopped after the Nal solution developed a blue color indicating that all the unsaturation had been consumed. The reaction mixtures were then allowed to warm to room temperature and heated for one hour at 40 C with Zn powder/acetic acid (1 1 molar ratio) to convert the ozonized groups on the polymers to aldehyde groups. 

Morse, D.E. (1999b) Sibcon biotechnology Proteins, genes and molecular mechanisms controlling biosilica nanofabrication offer new routes to polysiloxane synthesis, in Organosilicon Chemistry IV From Molecules to Materials (eds N. Auner and J. Weis), Wdey-VCH, Weinheim, pp. 5-16. 

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