New Ultra High CIS Polybutadiene Through a Novel Neodymium Catalyst

A significant improvement in the catalytic activity of Nd-based catalyst for 1,3-butadiene polymerization has been achieved using a novel neodymium compound, NdH(neodecanoate)4 (Nd( neodecanoate)3 (neodecanoic acid)). The neodymium compound was characterized with a matrix assisted laser desorption ionization (MALDI) mass spectroscopy, with a synchrotron X-ray absorption spectroscopy (XAS), and with computer simulations. A distinguished molecular ion peak (m/z=838.7, [M]) and a pronounced absorption edge are observed in the mass and in the Nd-LIII XANES(X-ray absorption near edge structure) spectra of NdH(neodecanoate)4, respectively, which evidence its monomeric structure. An active-center of the monomeric Nd-catalyst is fully optimized by density functional method (B3LYP/CEP-31G), in which neodymium(III) is coordinated with carboxylate, allylic active end, penultimate double bond, and chloride. The bond distances are Nd-C1 2.586 A˚, Nd-C4 2.741 A˚, Nd-C5 2.738 A˚, Nd-Cl 2.651 A˚, and Nd-O1 2.167 A˚, respectively. The Nd-catalyst shows a high activity (1.6×106 g/Nd md·h) and produces polybutadiene with 99% cis content. The ultra high cis polybutadiene produced by the Nd-catalyst exhibits excellent physical and mechanical properties such as high abrasion resistance, rebound, tensile properties and remarkably low heat build-up, which will greatly improve tire performance.