Nucleation in Emulsion Polymerization: Another Step towards Non-Micellar Nucleation Theory

• Published in: Macromolecular symposia Vol. 259; no. 1; pp. 264 - 273
• Main Authors: Nazaran, Pantea, Tauer, Klaus
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.12.2007; WILEY‐VCH Verlag; Wiley
• Subjects: 2,2′‐azobisisobutyronitrile; 2′-azobisisobutyronitrile; Agglomeration; Applied sciences; Emulsifiers; Emulsion polymerization; Exact sciences and technology; Micelles; Nucleation; Oligomers; Organic polymers; particle nucleation; Physicochemistry of polymers; Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts; seeded emulsion polymerization; Seeds; Styrenes; Free radical polymerization; Emulsion polymerization; Early phase; Reaction mechanism; Styrene polymer; Experimental study; Seeded polymerization
• ISBN: 9783527323562; 3527323562
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/masy.200751331

Comprehensive experimental results of the nucleation stage of styrene emulsion polymerization in the absence as well as in the presence of emulsifier at different concentrations are presented. In addition, the influence of initiator type and presence of seed particles are studied. The nucleation mechanism is verified by means of on‐line monitoring of the optical transmission and the conductivity of the aqueous phase. Results prove that micelles do not alter the nucleation mechanism which comprises the initiation of water soluble oligomers in the aqueous phase followed by their aggregation into colloidally stable latex particles. Surfactants assist with nucleation as they lower the activation free energy of particle formation. Contrary, in the presence of seed particles above a critical volume fraction the formation of new particles can be suppressed.