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3829024 
Journal Article 
High Molecular Weight Poly (methacrylic acid) with Narrow Polydispersity by RAFT Polymerization 
Pelet, JM; Putnam, D 
2009 
1 
Macromolecules
ISSN: 0024-9297
EISSN: 1520-5835 
42 
5 
1494-1499 
WOS:000263883000017 
Poly (methacrylic acid) is an adaptable macromolecule that offers many benefits in the development of new materials for a host of applications. Herein we report the reversible addition-fragmentation chain transfer (RAFT) polymerization of methacrylic acid (MAA) under a range of synthesis conditions by adjusting the ratio of reactants and the type of solvent employed. The RAFT system was composed of 4,4-azobis(cyanopentanoic acid) and 4-cyanopentanoic acid dithiobenzoate as the radical initiator (I) and chain transfer agent (CTA), respectively. This system was previously applied to synthesize MAA oligomers, but high molecular weight MAA homopolymers, to our knowledge, have yet to be reported. Three distinct [MAA](0):[I](0):[CTA](0) ratios (150:0.25:1, 250:0.25:1, and 150:0.1:1), in addition to two solvents (methanol and water/1,4-dioxane), initial monomer concentration and pH were evaluated and contrasted. It was determined that the polymerization evolved in a controlled fashion particularly in methanol. In addition, by adjusting the reactant ratios, we were able to obtain MAA homopolymers with molecular weights up to 113 900 with narrow polydispersities (similar to 1.13) using methanol as the solvent of choice.