Particle Formation in RAFT-Mediated Emulsion Polymerization: A Calorimetric Study

• Published in: Macromolecular symposia Vol. 275; no. 1; pp. 24 - 34
• Main Authors: Leswin, J.S.K, Meuldijk, J, Gilbert, R.G, van Herk, A.M
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Weinheim Wiley-VCH Verlag 01.01.2009; WILEY-VCH Verlag; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Acrylates; Applied sciences; Calorimetry; controlled radical polymerization; Emulsion polymerization; Exact sciences and technology; macro-RAFT agent; Monitoring; Monomers; Organic polymers; particle nucleation; Physicochemistry of polymers; Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts; reaction calorimetry; Styrenes; Surface chemistry; Acrylic acid ester; Organic trithiocarbonate; Polymerization modifier; Acrylic acid copolymer; Butyl acrylate polymer; Telechelic polymer; Reagent polymer; Living polymer; Experimental study; Butyl acrylate copolymer; Free radical polymerization; Chain transfer; Emulsion polymerization; Preparation; Styrene; Diblock copolymer; Styrene polymer; Chemical reactivity; Semicontinuous; Amphiphilic polymer; Styrene copolymer
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/masy.200950103

Ab initio RAFT-mediated semi-continuous emulsion polymerizations with controlled monomer feed have been studied by reaction calorimetry. This online monitoring technique provided detailed information about the onset of the nucleation period in semi-batch processes for emulsion polymerization of styrene and n-butyl acrylate. The reactions were carried out under controlled radical polymerization conditions by employing amphipathic macro-RAFT agents of various degrees of surface activity. For n-butyl acrylate as well as for styrene the more surface active polymeric macro-RAFT agents led to higher initial polymerization rates. Polymerizations with hydrophobic macro-RAFT agents also adapted more quickly to an increased monomer feed than polymerizations with hydrophilic macro-RAFT agents.This points to the presence of more particles when a hydrophobic macro-RAFT agent is used. Hydrophobic macro-RAFT agents demonstrated to be promising for producing latex products with a proper control of particle number and particle size distribution.