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Polymerization via RAFT in solution and miniemulsion

Grant number: 06/05739-0
Support type:Regular Research Grants
Duration: December 01, 2006 - November 30, 2009
Field of knowledge:Engineering - Materials and Metallurgical Engineering
Principal Investigator:Amilton Martins dos Santos
Grantee:Amilton Martins dos Santos
Home Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil

Abstract

The recent development of controlled free radical techniques have enable researchers to synthesized block-copolymers under less stringent conditions than those necessary for living ionic polymerizations. These new techniques of polymerization, mainly those mediated by reversible chain transfer agents by the way of addition-fragmentation mechanism (RAFT – Reversible Addition-Fragmentation Chain Transfer), have allowed working under similar conditions as used in free-radical polymerizations and offer the desired level of control over macromolecular structure and molar mass with low polydispersity. Despite of the advantageous effects in applying the RAFT process in compartmentalized system such as emulsion as well as miniemulsion polymerizations, this technique do not show the same successful of the bulk and solution polymerizations. The main problems that have been reported are loss of control of molar mass and polydispersity, coagulum formation and phase separations. Overcoming these problems is a challenge in utilizing the RAFT polymerization in heterogeneous media as emulsion and miniemulsion. The goal of this work is the synthesis of different RAFT agents to be applied in the synthesis of block copolymers by both, solution polymerization and a new process, the miniemulsion polymerization. We are still intending to synthesize RAFT macro-agents to be utilized in synthesis of cationic, anionic and non-ionic lattices by means of ab-initio emulsion polymerization. (AU)