Atom transfer radical polymerization of methyl methacrylate with α,α,α′,α′-tetrachloroxylene as an initiator

The homogeneous ATRP of methyl methacrylate (MMA) using alpha,alpha,alpha',alpha'-tetrachloroxylene (TCX)/CuCl/N,N,N',N '',N ''-pentamethyldiethylenetriamine (PMDETA) as the initiating system has been successfully carried out. The kinetic plots showed first order relationship vs. monomer concentration. Well-controlled polymerizations with low polydispersities (M-w/M-n =1.15-1.25) polymers have been achieved. The molecular weights increased linearly with monomer conversions and were close to the theoretical values, indicating high initiation efficiency. The polymerization rate increased significantly with an increase of TCX concentration. The rate of polymerization was about 0.6 orders with respect to the concentration of initiator. The polymerization rate increased significantly with an increase of CuCl concentration. The dependence of ln k(p)(app) on ln ([CuCl](0)) indicated a 0.91 order. The apparent activation energy was calculated Delta E-app(not equal)=43.3 KJ/mol, and the enthalpy of the equilibrium, Delta H-eq(0) , was estimated to be 21.1 KJ/mol. The structure of obtained PMMA was analyzed by means of H-1 NMR spectroscopy. The result proved that the TCX acted as a bifunctional initiator for ATRP of MMA.