Poly(ethylene oxide) (PEO) macromonomers with hydrophobically enhanced styryl end groups were prepared by three methods. The first consists of polymerization of ethylene oxide (EO) with potassium alkoxide of mono(t-butyldimethylsilyl)ether of 1,10-decanediol, termination with methyl iodide, desilylation with tetra-n-butylammonium fluoride, followed by coupling with p-vinylbenzyl chloride to afford a p-vinylbenzyloxydecyloxy-ended macromonomer. The second is a simpler method, consisting of polymerization of EO with a simpler potassium alkoxide and termination with p-styrylalkyl bromide to afford a p-styrylalkyloxy-ended macromonomer, but the termination was accompanied with a rather abundant side reaction due to E2 elimination to yield p-styrylalkene and hydroxy-ended PEO. This shortcoming could be overcome by the third method of transforming the hydroxy end group by reacting with about five-fold molar excess of sodium hydride and p-styrylalkyl bromide, except for p-styrylethyl bromide which exclusively reacted by E2 elimination to give p-divinylbenzenc. The radical homopolymerizations of the macro monomers obtained were found to be very rapid in water, particularly for those with more hydrophobic styryl end groups, supporting our previous idea of the organized micellar polymerization mechanism for these amphiphilic PEO macromonomers.

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Keywords: hydrosilylation polymerization self-polyaddition silicon containing polymer macromonomer INTRODUCTIONHydrosilylation is a well-known methodology in organic synthesis, which takes place under mild conditions to produce various alkylsilane compounds almost quantitatively.' In the polymer synthesis, addition of hydrosilyl (Si -H ) group across double bonds has been used to prepare blocks, * grafts, and network polymer^.^ However, the direct use of hydrosilylation reaction in preparation of organosilicic polymers has been limited so far. Hydrosilylation between a,@-divinyl compounds and a+-bis ( hydrosilyl ) compounds has been shown to afford organosilicic polymer^.^ However, terminal structure of these polymers obtained from such a two-component polyaddition reaction is difficult to control. Since Si -H group is inert to C -C unsaturated bonds without catalyst, the compounds possessing both vinyl and Si -H groups exist stable under normal conditions. Such compounds including dialkylvinylsilanes6 and diarylvinylsilanes have been synthesized and polymerized using y-radiation or platinum catalyst, respectively, to afford organosilicic polymers. These reactions required severe conditions, and no detail was reported about the terminal structure, the molecular weights, and characterization of the resulting polymers.We have prepared new monomers ( 3 ) having both vinyl and Si -H groups. Thus the transition metal catalyst can initiate self-polyaddition of such monomers. The resulting polymers having polymerizable vinyl group at the end of the chain are novel type of macromonomers containing silicon atoms. Thus as a typical and preliminary example, we report here the synthesis of styryl terminated organosilicic macromonomers using a self-polyaddition reaction between vinyl and Si -H groups, which we term "hydrosilylation polymerization." This is a convenient one-pot synthesis of macromonomers containing a unique structure of poly (arylene silylethylene) or poly (aralkylene silylethylene) . EXPERIMENTAL (4-Vinylphenyl)dimethylsilane ( 3a)A T H F solution of (4-vinylphenyl) magnesium chloride (70 mmol, 100 mL) was added dropwise to a solution of