Amphiphilic gradient poly(styrene-co-acrylic acid) copolymer prepared via nitroxide-mediated solution polymerization. Synthesis, characterization in aqueous solution and evaluation as emulsion polymerization stabilizer

C. Lefay , B. Charleux (1) , M. Save (2) , C. Chassenieux (3) , O. Guerret , S. Magnet

1 LCP - Chimie des polymères
2 IPREM - Institut pluridisciplinaire de recherche sur l'environnement et les matériaux
3 LCMD - Laboratoire Colloïdes et Matériaux Divisés

A well-defined, amphiphilic poly(styrene-co-acrylic acid) copolymer was synthesized in a single step by nitroxide-mediated controlled free-radical copolymerization of styrene and acrylic acid, without protection of the acid groups: Mn=6500 g mol-1, Mw/Mn=1.5 and a composition of FAA=0.70±0.03 in acrylic acid. In addition to the good control over molar mass and molar mass distribution, the copolymer exhibited a narrow composition distribution with a slight gradient. Such copolymer was an efficient stabilizer for the emulsion polymerizations of styrene and of mixtures of methyl methacrylate and n-butyl acrylate, until 45 wt% solids. A low amount (typically 3-4 wt% based on the monomer(s)) was needed for a good stabilization. This is approximately a decade lower than the required amount of random, amphiphilic copolymers prepared via conventional free-radical polymerization. The performances were, however, below those of analogous diblock copolymers, but the great advantage is the very easy synthetic procedure. © 2006 Elsevier Ltd. All rights reserved.

Domaines: Polymères

C. Lefay, B. Charleux, M. Save, C. Chassenieux, O. Guerret, et al.. Amphiphilic gradient poly(styrene-co-acrylic acid) copolymer prepared via nitroxide-mediated solution polymerization. Synthesis, characterization in aqueous solution and evaluation as emulsion polymerization stabilizer. Polymer, 2006, 47 (6), pp.1935-1945. ⟨10.1016/j.polymer.2006.01.034⟩. ⟨hal-01563808⟩