title: Atom Transfer Radical Polymerization of Methacrylic Acid: A Won Challenge.
abstract: Polymerization of acidic monomers is one of the biggest challenges for atom transfer radical polymerization (ATRP). An intramolecular cyclization reaction leading to the loss of the C-X chain-end functionality was found to be the main reason for the partial termination of the growing polymer chains. Three approaches were used to overcome this problem: using Cl as the chain-end halogen, lowering the pH (to 0.9), and increasing polymerization rate. Methacrylic acid (MAA) was polymerized by both electrochemically mediated ATRP and supplemental activator and reducing agent ATRP up to high conversion (>90%), in t ≤ 4 h at 25 °C, using inexpensive and nontoxic reagents (NaCl, diluted HCl, water). Control over molecular weight (MW) dispersity was satisfactory, and MWs were in agreement with theoretical values. The "livingness" of the process was confirmed by an electrochemical switch, used to repeatedly and periodically deactivate/reactivate growing chains.
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.|Center for Molecular Engineering, Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Marco
authors.initials: M
authors.lastname: Fantin
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
authors.forename: Abdirisak A
authors.initials: AA
authors.lastname: Isse
authors.affiliation: IENI-CNR, Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Venzo
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
authors.forename: Armando
authors.initials: A
authors.lastname: Gennaro
authors.affiliation: Center for Molecular Engineering, Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Matyjaszewski