| 초록 |
There has been recent interest in the use of soluble transition metal catalyst for 1,4-polymerizations of isoprene and 1,3-butadiene to obtain high molecular weight polymers with low polydispersities as efficient low-cost materials for improved synthetic rubber. In the present work, we have done the polymerization of isoprene (IP) using bis(benzimidazolyl) ligands derived transition metals complexes of Co(II) and Cr(III) with ethylaluminum sesquichloride (EAS) and methylaluminoxane (MAO) as cocatalyst, respectively. Both of them were highly active yielding polymers of high molecular weights. The microstructure analysis by NMR, the Co(II) catalysts were stereospecific towards 1,4-cis content products(~83%), and on the other hand Cr(III) catalysts, when activated with MAO, resulted highly in 1,4-trans polyisoprenes. |
