Among ZieglerNatta catalysts used for 1,3butadiene (1,3BD) polymerization, the advantage of a neodymium (Nd)based catalyst is that it provides butadiene rubber (BR) with a high content of cis1,4 configuration and a low amount of vinyl1,2 units. Whereas, a cobalt (Co)based catalyst can produce BR with a low content of trans1,4 configuration. Thus, this research was aimed to prepare BR containing a high content of cis1,4 configuration with low amounts of both trans1,4 and vinyl1,2 units using a combination of Nd and Cobased Ziegler/Natta catalysts with triethyl aluminum (TEAL) and diethyl aluminum chloride (DEAC) acting as a cocatalyst and a chlorinating agent, respectively. The effects of the molar Co/Nd ratio, TEAL concentration, DEAC loading, 1,3BD content, solvent type, and reaction temperature on %conversion, microstructures, molecular weight, and molecular weight distribution of the obtained BR (Co/NdBR) were evaluated. The Co/NdBR having >97% of cis1,4 configuration, <2% of trans1,4 structure, and <1% of vinyl1,2 unit with >80% conversion was achieved when 3.01 M of 1,3BD concentration was treated in a toluene/cyclohexane mixture (7/3 [w/w]). The Co/NdBR exhibited no gel formation with high mechanical performance, which was equivalent to commercial BR produced from a Ndbased catalyst system. POLYM. ENG. SCI., 55:1421, 2015. © 2014 Society of Plastics Engineers
