Methyl methacrylate (MMA) was polymerized with the rare earth coordination catalyst system of Nd(O? Pr) 3 in toluene. The influences of various ligands in neodymium complexes, molar ratio of Al/Nd, catalyst concent...Methyl methacrylate (MMA) was polymerized with the rare earth coordination catalyst system of Nd(O? Pr) 3 in toluene. The influences of various ligands in neodymium complexes, molar ratio of Al/Nd, catalyst concentration, catalyst aging time, solvents, the third component CCl 4, temperature and time on the polymerization of MMA were studied. The results showed that the polymerization conversion reached more than 80% at a catalyst concentration of 9 2×10 -3 mol/L. The appropriate molar ratio of CCl 4/Nd was 4. Hydrocarbon was preferred for the polymerzation to obtain a high conversion and a high M W of PMMA. The 1H NMR spectra of PMMA indicated that the lower the temperature, the higher the syndiotactic content of PMMA was obtained.展开更多
Neodymium phosphonate [Nd(P-204)(3)] combined by di(n-butyl) magnesium [Mg(n-Bu)(2)] with hexamethylphosphoramide (HMPA) was first found to be an effective catalyst. The results of infrared spectrum and elemental anal...Neodymium phosphonate [Nd(P-204)(3)] combined by di(n-butyl) magnesium [Mg(n-Bu)(2)] with hexamethylphosphoramide (HMPA) was first found to be an effective catalyst. The results of infrared spectrum and elemental analysis showed that the copolymers containing carbonyl group were produced.展开更多
文摘Methyl methacrylate (MMA) was polymerized with the rare earth coordination catalyst system of Nd(O? Pr) 3 in toluene. The influences of various ligands in neodymium complexes, molar ratio of Al/Nd, catalyst concentration, catalyst aging time, solvents, the third component CCl 4, temperature and time on the polymerization of MMA were studied. The results showed that the polymerization conversion reached more than 80% at a catalyst concentration of 9 2×10 -3 mol/L. The appropriate molar ratio of CCl 4/Nd was 4. Hydrocarbon was preferred for the polymerzation to obtain a high conversion and a high M W of PMMA. The 1H NMR spectra of PMMA indicated that the lower the temperature, the higher the syndiotactic content of PMMA was obtained.
文摘Neodymium phosphonate [Nd(P-204)(3)] combined by di(n-butyl) magnesium [Mg(n-Bu)(2)] with hexamethylphosphoramide (HMPA) was first found to be an effective catalyst. The results of infrared spectrum and elemental analysis showed that the copolymers containing carbonyl group were produced.
