Organotellurium Compounds as Chain Transfer agents for Living Radical Polymerization

Abstract

Synthetic and mechanistic aspects of organotellurium‐mediated living radical polymerization (TERP), which utilizes divalent organotellurium compounds as controlling agents, are discussed. TERP predominantly proceeds by the degenerative chain transfer mechanism for the activation/deactivation of the dormant/radical species, while reversible termination by thermolysis and photolysis of carbon‐tellurium bonds also contributes to a small extent. The high reactivity of organotellurium compounds towards polymer‐end radicals in the degenerative chain transfer reaction ensures the high control of molecular weight and molecular weight distribution of the resulting polymers. Addition of ditellurides considerably increases the control of the polymerization by altering the activation/deactivation mechanism. TERP possesses several synthetic advantages, such as high versatility of monomer families, high versatility of block copolymer synthesis, high compatibility of polar functional groups and solvents, high versatility for selective synthesis of end‐functionalized polymers, and high reliability for scale up for the industrial applications. These characteristics offer excellent opportunities for macromolecular engineering in the synthesis of new polymeric materials for various applications.

Termination Mechanism in the Radical Polymerization of Methyl Methacrylate and Styrene Determined by the Reaction of Structurally Well-Defined Polymer End Radicals

“…We utilized organotellurium-mediated radical polymerization (TERP) in this study for the preparation of the precursors of the polymer-end radicals, although several methods for the living radical polymerization have also been developed . The most important advantage of TERP over other methods in clarifying the termination mechanism is the efficient activation of the organotellurium dormant species by photoirradiation to generate the corresponding polymer-end radicals .…”

Synthesis of Concentrated Polymer Brushes via Surface-Initiated Organotellurium-Mediated Living Radical Polymerization

“…We previously developed an organotellurium-mediated controlled/living polymerization (TERP). − The most characteristic feature of TERP is its high versatility among monomer families; the same organotellurium chain transfer agent (CTA) can control the polymerization of both conjugated and nonconjugated monomers. − In addition, TERP is highly compatible with various functional groups and with conditions such as acidic and basic environments. − Therefore, the application of TERP in the synthesis of CPBs represents an excellent opportunity to create new materials and to expand the potential of surface engineering. We report here the synthesis and immobilization of a CTA on silicon wafers and silica nanoparticles (SiPs) for use in surface-initiated TERP and its application to the synthesis of CPBs from both conjugated and unconjugated monomers.…”