Synthesis of hydroxy- and dihydroxy-end-capped poly(n-butyl acrylate)s and their use as reactive stabilizers for the preparation of polyurethane latexes

Well-defined hydroxy end-functionalized poly(n-butyl acrylate)s (PBA-OH and PBA-(OH)(2)), were prepared by atom transfer radical polymerization (ATRP) and used as reactive stabilizers for the preparation of polyurethane in dispersed medium. PBA-OH was obtained by end-capping the growing poly(n-butyl acrylate) chains with allyl alcohol added in excess at the end of the polymerization. The two hydroxyl functions of PBA-(OH)2 were fixed at one end of the poly (n-butyl acrylate) chains either by initiation or by chain-end functionalization reactions. The latter were protected under the form of cyclic acetal and attached either to the initiator bearing a secondary bromine or to the terminating agent carrying a poorly reactive vinylic unsaturation. PBA-OH and PBA(OH)(2) have been successfully used as reactive stabilizers (surfmers) to prepare core-shell polyurethane particles in dispersed medium. The final particle size was found to be very much dependent to parameters such as the molar mass, concentration and valence of the reactive stabilizer as well as the manner of addition of the reactants during the procedure.