2ATRP Atom Transfer Radical Polymerization Halogen transfer through metal complex induced reversible heterolysisresulting in the formation of reversible free radicals to initiate and propagate polymerization.
3Formation of induced reversible free radical? R – Propagating species/ tethered initiatorX – halogen atom (usually Cl/Br)RXMnMn – Transition metal in lower oxidation state(Copper is most commonly used). .Ligand – Lewis base to stabilize transition metal forming a complex
13Functionality Functional monomers Modification post polymerization eg. Glycidyl methacrylateModification post polymerizationFunctional ATRP initiatorseg. Glycidyl 2-bromopropionateEnd-group transformation chemistry
14Shortcomings of ATRPOxygen hinders polymerization forming stable copper oxides.DegassingAddition of reducing agent (Cu) provides toleranceNo control over tacticity due to radical nature.Unwanted catalyst colorCatalyst removal problems