Abstract: Polymerization of styrene was catalyzed by a new late transition metal complex catalyst system based on bis-(β-ketonaphthylamino) nickel(Ⅱ)/MAO (methylaluminoxane). The influence of polymerization conditions such as polymerization temperature, Al/Ni molar ratio, monomer concentration, and polymerization time was investigated. The obtained polymer was characterized by gel permeation chromatography, proton and 13C nuclear magnetic resonance, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and wide-angle X-ray diffraction. The results indicated that the catalyst system exhibited high catalytic activity. The structure analysis result of the polymer demonstrated that the above catalyst system initiated styrene to yield atactic polystyrene with moderate molecular weight and narrow molecular weight distribution (Mw/Mn＜1.6).

Key words: nickel, complex, late transition metal catalyst, styrene, polymerization, polystyrene