Polymerization Of Methyl Methacrylate Catalyzed By Novel L-arginine Schiff Base Complexes Without Of Any Cocatalyst

In this dissertation, we synthesized Schiff base ligands 3,4-HDIA, (2,4-HDIA, HSALA) deriving from L-arginine and 3,4-dihydroxybenzaldehyde (benzaldehyde, 2,4-dihydroxybenzaldehyde,) which were characterized by ~1H NMR spectra.We then synthesized transition metal Cu(â…¡), Co(â…¡), Ni(â…¡) and lanthanide L-arginine Schiff base complexes which were characterized with elemental analysis and U-V spectra.These complexes were then applied in the polymerization of methyl methacrylate monomer without any cocatalyst. Some Schiff base-metal complexes can catalyze polymerization without any cocatalyst. The influence of reaction conditions, such as the molar ratio of MMA/M, reaction temperature and times, as well as the catalyst concentration, was investigated in detail. The molecular weight and polydispersity of PMMA were measured separately by viscometry and GPC method, and the structure of PMMA was characterized by ~1H NMR. Polymethyl methacrylate (PMMA) with high viscosity-average molecular weight (10~6), narrow polydispersity (2.0) and 61% syndiotacticity was obtained, which means these complexes have high catalytic activity for the polymerization of MMA.Trough the study we found Some Schiff base-transition metal or Ln metal complexes were excellent catalysts for polymerization of the polar monomer (MMA). Compared with conventional Ziegler-Natta catalyst, their lower cost, easier preparation, higher activity and narrower molecular weight distribution make them much more outstanding. Through many experiments, we found that the most important factor influencing the polymerization is the structure of Schiff base-transition metal or Ln metal complexes.