The first-generation poly(amidoamine)(PAMAM) dendrimer was modified by the salicylaldehyde via a Schiff-base condensation reaction

and reacted with TiCl4·2THF to give rise to a novel dendrimer-supported titanium complex.Its architecture was determined by 1H-NMR

ICP-AES and ESI-MS.The application as a catalyst precursor

activated by methylaluminoxane (MAO)

for ethylene polymerization was also carried out.The results revealed that the metallodendrimer catalyst for the polymerization of ethylene had a higher activity (56.56 kg PE/(mol Ti·h)

at a ratio of Al/Ti=1000) in comparison with the corresponding phenoxy-imine complexes.The melting point temperature (Tm) of the polyethylene as determined by DSC was 138℃

and the crystallization temperature (Tc) was 116℃.The apparent molecular weight of the polyethylene(Mv) was 1.28×106 by viscometry.The results implied that these polymers were linear low-density polyethylene.The viscoelastic properties of the polyethylene also indicated that the polyethylene was of ultra high molecular weight.