Dispersion Polymerization of Polystyrene Latex Stabilized with Novel Grafted Poly(ethylene glycol) Macromers in 1-Propanol/Water

A novel hydrophilic macromer adapted for chemical grafting has been synthesized. It consists of methyl-end-capped poly(ethylene glycol) functionalized with a urethane terminus. Dispersion polymerization of styrene in an alcohol/water medium in the presence of the macromer allows chemical grafting of the macromer to the surfaces of the developing polystyrene (PS) latex particles. Scanning and transmission electron microscopies confirm the formation of spherical, submicron polystyrene particles. Transmission electron microscopy of films prepared from the latex particles also permits direct visualization of the stabilizing macromer layer grafted on the PS particle surfaces. Data acquired from proton nuclear magnetic resonance reveal a direct correlation between the concentration of macromer in the reaction mixture and the amount grafted to the latex particles. Rheological techniques are employed to (i) discern the stabilization efficacy of the macromer and (ii) identify correlations between latex and flow characteristics.