Applied aspects - Synthesis of Polymers and Materials

Barton and coworkers carried out the first hydrosilation polymerization of an ethynylhydrosilane that led to soluble, well-characterized, low-medium molecular weight poly(methylphenylsilylenevinylene) as a glassy polymer in 95% yield, using H2PCI6 in THF as catalyst.Poly(dimethylsilylenevinylene) was also prepared similarly [Eq. (29)]. Interestingly, only terminal (anti-Markovnikov) addition of SiH was observed for the polymers 45, as supported by NMR data, and it also appears that the hydrosilation was highly stereoselective towards one isomeric backbone structure. Flexible fibers drawn from the Ph/Me polymer melt could be UV-cross-linked and pyrolyzed to yield ceramic fibers. 

A number of silylene-vinylene-phenylene type polymers containing 1-3 ferrocene moieties per repeat unit have been synthesized by Sheridan s group via 

Liquid crystals are of course of immense importance to the electronics industry. Side-chain liquid-crystalline siloxanes prepared via hydrosilation of mesogens with poly(methylhydrosiloxane) [Eq. (30), e.g.], and their phase behavior studies using DSC, optical microscopy and X-ray diffraction have been reported. 

4 -oxybis(benzainidopropyl) rungs and a naphthyl substituent on each silicon has been synthesized via hydrosilation followed by H-bonding-templated hydrolysis-condensation of the monomeric bis(diethoxysilane).  

Silicone polyethers (SPE) 51, also known as silicone-copolyols (SCP), which are readily prepared via hydrosilation [Eq. (31)], form a very important class of copolymers in the area of commercial surfactants. Their utility, however, goes beyond the surface properties as they are also highly suited for ion conduction in polymeric liquid, gel or solid battery appUcations. A good number of publications have appeared on this utility, and ionic conductivities approaching 1.0 x 10 S/cm appear within reach in the near future. Even oligoethylenoxysilanes and short-chain siloxanes show promise for good liquid electrolyte conductance. Polysiloxanes with pendent cycKc carbonate and sulfonate groups were also reported earher for this application. 

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