An activated neodymium-based catalyst for styrene polymerization

Coordination polymerization of styrene with a ternary catalyst system composed of catalyst neodymium tricarboxylate (Nd), co-catalyst Al(i-Bu)3 (Al) and chlorinating agent trichloroethane (Cl) was carried out in cyclohexane. The effects of the catalyst system preparation procedure and of the reaction conditions on catalytic activity, molecular weight and molecular weight distribution of the resultant polymers were investigated. The catalytic activity depended mainly on the molar ratios of Al/Nd and of Cl/Nd and on the ageing temperature and polymerization temperature. High polymerization conversion and high catalytic activity could be obtained at high Al/Nd ratios and/or at high ageing temperature. The catalyst system exhibited high activity of 8.32 × 104 g polystyrene (mol Nd h)−1 at 50 °C. The molecular weight of the polymers obtained reached high weight-average (Mw) values (Mw = 4.35 × 105 g mol−1) when Al/Nd = 8, but relatively low values (6000–11 000 g mol−1) at high Al/Nd ratios. Copyright © 2005 Society of Chemical Industry