Polymerization of n-butyl methylacrylate using bis(β-ketoamino) nickel(II)/MAO catalytic systems

Abstract

The polymerizations of n-butyl methylacrylate (nBMA) were carried out using bis(/3-ketoamino)nickel(II) complexes (Ni[CH3C(O)CHC(NR)CH 3]2: R = phenyl, 1; R = naphthyl, 2) in combination with methylaluminoxane (MAO) in toluene. The effect of parameters such as polymerization temperature, Al/Ni molar ratios, polymerization time, and monomer concentration, on catalytic polymerization activity and polymer molecular weights, were examined in detail. Both of the nickel(II) catalytic systems exhibited moderate activity, and produced P(nBMA) with high molecular weight and relatively broad molecular weight distribution (Mw/Mn = 2.0∼3.0. The obtained polymer has been characterized by means of FTIR, 1H NMR, 13C NMR, DSC, and WAXD technique and was confirmed to be syndio-rich stereospecific P(nBMA).