Low Cis Polymerization of Butadiene Using TiCl4 and Bisupported with SiO2/MgCl2(Ethoxide Type)/TiCl4 Catalysts
Abstract To obtain low cis polymer of butadiene (PBR), heterogenous and homogeneous Ziegler-Natta catalyst of TiCl4 were used. SiO2 and Mg(OEt)2 were used as supports for the heterogenous catalyst, while TiCl2 was used as a soluble catalyst. Triisobutylaluminium (TIBA) was used as a cocatalyst. Optimum molar ratio of Al/Ti = 1.5 : 1 and Al:Ti = 13 : 1 were obtained for TiCl4/TIBA and SiO2/MgCl2 (ethoxide type)/TiCl4/TIBA catalyst systems, respectively, regarding productivity of the catalysts. Effect of the temperature of 25–65 °C on polymerization was studied for the bisupport one; while for the TiCl4 temperature control was difficult. This could be due to the obtained high gel content of polymer. The highest yield of PBR was obtained at 55 °C using the bisupported catalyst. Addition of H2 as a chain transfer agent decreased cis%, gel content and the yield of polymer obtained. Increasing polymerization temperature when H2 was used was negligible, which had an affect on the gel content of the polymer. Productivity of the bisupported catalyst was higher than the TiCl4 catalyst itself and the polymerization temperature was under control as well. Polymer with cis content of 4 to 65% was obtained using different catalyst and different polymerization conditions.