Emulsion copolymerization of styrene with monomeric emulsifiers

Abstract

Monomeric emulsifiers with different copolymerization reactivities were used as stabilizers in emulsion polymerization of styrene initiated by 2,2'azobisisobutyronitrile (AIBN). A significant change in emulsifier function was observed between equal micellar concentrations of surface-active sodium sulfopropyl alkyl maleates and the corresponding sodium sulfopropyl dodecyl fumarate. In the presence of less reactive maleates, copolymerization mainly occurs in the interface of the monomer swollen particles, while copolymerization with the fumarate in the first period of emulsion polymerization leads to polyelectrolyte formation in the water phase.

Reactive Surfactants

“…It is surprising that based on these crude data some reasonable predictions are possible. So for instance, it has been experimentally observed that sodium sulfopropyl alkyl maleates show a different behavior than the corresponding fumarates in styrene emulsion polymerization [39]. At 20 % conversion all monomeric fumarate SURFMER is used up whereas, the maleates start to react in a larger extend at 80 % conversion.…”

“…From the r-values (Table I) one can predict that the maleate SURFMERS represent case 3 whereas the fumarates more likely represent case I. The copolymer consisting of fumarate SURFMER and styrene act as stabilizer in that particular case [39].…”

Reactive surfactants in heterophase polymerization

“…Thus, when acceptable amounts of surfmers are used (1 to 5 wt% based on monomers) NMR is often not sufficiently accurate, although Charleux et al [74] were able to perform a quantitative analysis. Separation of the unreacted surfmer is possible by serum replacement [62,75] and by centrifugation [63,76,77]. However, serum replacement is very time consuming and centrifugation can only be used conveniently with high T g latexes.…”

“…Once separated from the particles, the unreacted surfmer can be determined by analyzing the serum. Twophase titration has been found useful for analyzing a variety of anionic surfmers [62] but interference from in situ formed surface-active oligomers is possible [63,76,77].…”

Reactive Surfactants in Heterophase Polymerization. 11. Particle Nucleation

“…Potassium persulfate (KPS), sodium dodecyl sulfate (SDS), potassium sulfate (KS), and sodium bicarbonate (SBC) were of analytical grade and used as received. The surfmer M12 was obtained from K. Stähler, Max Planck Institut für Kolloid und Grenzflächenforschung, and was synthesized according to methods described in the literature . The purity was approximately 92%.…”