MECHANISTIC STUDY OF CATALYTIC OXIDATIVE COPOLYMERIZATION OF 2-(N,N-DIMETHYLAMINO) ETHYL METHACRYLATE AND METHYL METHACRYLATE

The CuX/pentamethyldi-ethylenetriamine (PMDETA)-catalyzed oxidative copolymerization of 2-(N,N-dimethylamino) ethyl methacrylate (DMAEMA) and methyl methacrylate (MMA) was investigated. The kinetics were compared by varying the monomer ratio,catalyst concentration and the reaction temperature. The results showed that the copolymerization could proceed under the monomer ratio ([DMAEMA]: [MMA] = 10:0 similar to 5: 5), catalyst concentration ([CuCl/PM DETA(3)] = 3. 1 x 10(-5)mol/L similar to 6 x 10(-3)mol/L) and the reaction temperature (30 similar to 80 degrees C) which were investigated in the paper, and the molecular weight increased with the reaction time, while the molecular weight distribution maintained rather broad. It was showed from the H-1-NMR that there were DMAEMA units and MMA units in the copolymer, while the DSC indicated that the system of copolymer was partially compatible. The CuCl/PMDETA-catalyzed atom transfer radical polymerization (ATRP) of MMA using the so-obtained PDMAEMA as the macroinitiator was successful, confirming the presence of the C-Cl terminal functionality. Thus, the following mechanism might operate: 1) O-2 oxidized CuCl into [Cu(II)Cl](+) species; 2) [Cu(II)Cl](+) oxidized dimethylamino moiety into N-CH2 center dot radicals; 3) N-CH2 center dot radicals and [Cu(II)Cl](+) formed the reverse ATRP system. The above processes finally led to polymer with C-Cl end group.