Silicone multiblock copolymer

During the last 5 years, there have been several reports of multiblock copolymer brushes by the grafting-from method. The most common substrates are gold and silicon oxide layers but there have been reports of diblock brush formation on clay surfaces [37] and silicon-hydride surfaces [38]. Most of the newer reports have utilized ATRP [34,38-43] but there have been a couple of reports that utilized anionic polymerization [44, 45]. Zhao and co-workers [21,22] have used a combination of ATRP and nitroxide-mediated polymerization to prepare mixed poly(methyl methacrylate) (PMMA)Zpolystyrene (PS) brushes from a difunctional initiator. These Y-shaped brushes could be considered block copolymers that are surface immobilized at the block junction. 

Fig. 9. Dependence of the energy contribution on the filler (filled rubbers) or hard phase (thermo elastoplastics) content. 1 — filled silicone rubber1221 Sil-51 (A), Sil-4600 ( ) multiblock copolymer polyarylate-PDMS (O) us) graft copolymer of PDMS and AN ( x) 128>. 2 — Butyl rubber with high abrasion furnace black125). 3 — Butyl rubber with medium thermal black 125). 4 — SBR-filled rubber 126). 5 — aerosil //j Si-filled silicon rubber138). 6 — EPR-filled rubber 129,130). 7 — plastisized PVC filled with aerosil131132). 8 — SBS block copolymers 134)...

From such compounds, series of di-, tri- and multiblock copolymers were prepared with a large variety of structures including soft, hard, hydrophobic, hydrophilic, silicone or phosphonamide sequences [12]. 

During the last decade, more and more advanced techniques of living or controlled polymerization to prepare block copolymers have become available. It has become possible to prepare block copolymers of various architectures, solubility, and functionality [6]. Architectures comprise diblock, triblock, and multiblock copolymers arranged linearly, as stars or grafts. The solubilities vary from polar solvents such as water to media with very low cohesion energies such as silicon oil or fluorinated solvents. Control of functionality has become impor-... 

Ni, Y, Rulkens, R., and Manners, I. (1996) Transition metal-based polymers with controlled architectures Well-defined poly(ferrocenylsilane) homopolymers and multiblock copolymers via the living anionic ring-opening polymerization of silicon-bridged [l]ferrocenophanes. Journal of the American Chemical Society, 118,4102. 

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