The polymerization of methyl methacrylate with a new Nd(O-i-Pr)(3)-Al(i-Bu)(3) catalyst system

Methyl methacrylate (MMA) was polymerized with the rare earth coordination catalyst-system of Nd(O - i-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 CCl4, 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 x 10(-3) mol/L. The appropriate molar ratio of CCl4/Nd was 4. Hydrocarbon was preferred for the polymerzation to obtain a high conversion and a high <(M)over bar w> of PMMA. The H-1 NMR spectra of PMMA indicated that the lower the temperature, the higher the syndiotactic content of PMMA was obtained.