Anionic difunctionalization with 1,1-bis(4-t-butyldimethylsiloxyphenyl) ethylene. Synthesis of ω,ω-bis(phenol)-functionalized polystyrene condensation macromonomers

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Abstract

ω,ω-Diphenolpolystyrenes (6) can be synthesized in quantitative yields by reacting poly(styryl)lithium with 1,1-bis(4-t-butyldimethylsiloxyphenyl)ethylene (1), followed by methanol termination and hydrolysis with dilute acid. The initially formed 1,1-bis(4-t-butyldimethylsiloxyphenyl)alkyllithium can be reacted with additional styrene monomer to form a polystyrene internally substituted with two in-chain phenol groups after methanol termination and acid hydrolysis. The diphenol-substituted polystyrene condensation macromonomers have been characterized by end-group titration, size exclusion chromatography, thin-layer chromatography, and ultraviolet-visible, 1H and 13C NMR spectroscopy. Chain-extension reactions of 6 (Mn = 2.6 × 103g mol−1) with bis(trichloromethyl)carbonate produced the corresponding comb-type, branched polymer with estimated Mn(SEC, polystyrene standards) = 1.2 × 104g mol−1 and no detectable residual condensation macromonomer. The second order rate constants for the addition reaction of excess poly(styryl)lithium with 1 and with 1-(4-t-butyldimethylsiloxy-phenyl)-1-phenylethylene (3) have been estimated to be 1.7 × 10−3M−1/2S−1 and 3.2 × 10−3M−1/2S−1 respectively. A sigma value (σ) of −0.46 has been estimated for the t-butyldimethylsiloxy substituent.

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