Protection and polymerization of functional monomers, 22. Synthesis of well-defined poly(4-vinylbenzoic acid) by means of anionic living polymerization of N-(4-vinylbenzoyl)-N′-methylpiperazine, followed by deprotection

Abstract

Anionic polymerizations of N-(4-vinylbenzoyl)-N′-methylpiperazine (3a) and N-(4-vinylbenzoyl)morpholine (3b) were carried out in tetrahydrofuran at −78°C with oligo(α-methylstyryl)-dilithium, -disodium, and -dipotassium. The polymerizations of both 3a and 3b proceeded quantitatively to give stable living polymers having predicted molecular weights and narrow molecular weight distributions. Novel block copolymers, poly(3a)-block-polystyrene-block-poly(3a) and poly(3b)-block-polystyrene-block-poly(3b), were synthesized by using these living polymerization systems. Under acidic conditions (6 N HCl in 1,4-dioxane-water), quantitative hydrolysis of the amide linkage of the poly(3a) was achieved to give a well-defined poly(4-vinyl-benzoic acid).