2 ATRP Atom Transfer Radical Polymerization Halogen transfer through metal complex induced reversible heterolysisresulting in the formation of reversible free radicals to initiate and propagate polymerization.
3 Formation 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
13 Functionality Functional monomers Modification post polymerization eg. Glycidyl methacrylateModification post polymerizationFunctional ATRP initiatorseg. Glycidyl 2-bromopropionateEnd-group transformation chemistry
14 Shortcomings 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