Atom Transfer Radical Polymerization (ATRP) Of Methyl Methacrylate And Styrene Under Microwave Irradiation And Conventional Heating Processes

In this thesis, different multi-choloroxylenes used as initiators for ATRP was studied. The ATRP of Methyl methacrylate, using a , a ' -dichloroxylene (DC1X) as initiator, CuCl/N, N, N', N," N" -pentamethyldiethylenetriamine (PMDETA) as catalyst was successfully carried out under microwave irradiation (MI); Using the same catalyst system, ATRP of MM A and St using α, α, α', α'-tetrachloroxylene(TCX) as initiator were also successfully carried out under conventional heating processes(CH) ; at the same time Bifunctional or mutlfunctional polymer were obtained.It was found that plots of In ([M] o/[M]) vs. time and molecular weight evolution vs. conversion showed a linear dependence by the kinetic studies of ATRPs of MMA under MI, and that the "living'Vcontrolled nature of the polymerization systems was not changed under MI by a series of characterizations for polymers obtained (i.e. chain extension, analysis of end groups). Under identical polymerization conditions, the apparent constant of propagation (kpapp) under MI was 14.3 times larger than that under CH, indicating a significantly increase of the polymerization rates under MI. The concentration of Cu in the solution of this heterogonous system was determined; the results show that the concentration of Cu under MI is higher than that under CH within the same time. MI increases the dissolution of CuCl in the system; this may be one of reasons for applying MI to polymerization can enhance the rate of polymerization.The homogeneous ATRP using α, α, α', α' -tetrachloroxylene (TCX) / CuC I/ N, N, N', N", N" -pentamethyldiethylenetriamine (PMDETA) as the initiating system has been successfully carried out for methyl methacrylate. The kinetic plots were first order in monomer. Well-controlled polymerizations with low polydispersities (Mw/Mn = 1.15-1.25) has been achieved. The molecular weights increased linearly with monomer conversion and were close to the theoretical values, indicating high apparent initiator efficiency. Thepolymerization 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 apparent activation energy was calculated AEapp 43.3 kJ/mol, and the enthalpy of the equilibrium, AHeq0 was estimated to be 21.1 kJ/mol. It was approved that the TCX acted as the bifunctional initiator for ATRP of MMA through the structure analysis of obtained PMMA by means of !H NMR spectroscopy. In addition, ATRP of St using TCX as initiator was also carried out.