New immobilized catalyst system for atom transfer radical polymerization

2-( 8-heptadecenyl)-4, 5-dihydro-lH-imidazole-l-ethylamine ( OLC ) was synthesized from cw-9-octadecenoic acid and divinyl-triamine. CuBr/SiO₂-OLC and CuCl₂/SiO₂-OLC catalysts were prepared separately through chemically immobilizing OLC on silica gel surface to obtain SiO₂-OLC and then interacting SiO₂-OLC with CuBr or CuCl₂. The catalysts were used in atom transfer radical polymerization (ATRP) of methyl methacrylate with ethyl 2-bromopropionate as initiator. The catalysts were characterized by means of elemental analysis and FTIR. Relative molecular mass and its distribution of the poly (methyl methacrylate) obtained through the ATRP were measured by means of GPC. The result showed that kinetics of the ATRP catalyzed by CuBr/SiO₂-OLC or CuCl₂/SiO₂-OLC was first order reaction, relative molecular mass of the obtained polymer increased linearly with monomer conversion, which indicated the ' living ' /controlled nature of the polymerization, and relative molecular mass distribution of the polymer was low (the former was 1. 25 and the latter was 1. 33). The polymer solution obtained with CuCl₂/SiO₂-OLC catalyst was transparent and the catalyst could be reused.