The influence of Ni/Nd-based Ziegler-Natta catalyst on microstructure configurations and properties of butadiene rubber

摘要

Neodymium (Nd)-based ZieglerNatta catalyst has been well known for preparing polybutadiene rubber (BR) containing high, about 98, cis-1,4 configuration with extremely low gel content providing superior resistance to low-temperature fatigue and abrasion. However, its cost is more expensive than a conventional nickel (Ni)-based catalyst. The Nd-BR has poor processability with high cold flow due to its high linearity and molecular weight. To compare with a traditional process, the BR produced by Ni-based catalyst has higher level of branching resulting in the better processability, but it contains medium amount of gel. To balance the catalyst cost and the BR properties, this article reported the influence of a solution containing Ni- and Nd-based ZieglerNatta catalyst (Ni/Nd) using diethyl aluminum chloride and triethyl aluminum as co-catalysts on 1,3-butadiene (BD) conversion and physical properties of the elastomeric materials based on obtained rubber (Ni/Nd-BR). In the presence of toluene, the increase in the Ni/Nd molar ratio from 0.0/1.0 to 0.4/0.6 yielded Ni/Nd-BR containing cis-1,4 units of 9596 with significantly decreasing both levels of vinyl-1,2 and trans-1,4 configurations from 0.26 to 0.13 and 4.44 to 3.07, respectively. When cyclohexane was applied as the reaction media, 100 BD conversion was achieved and the Ni/Nd-BR had very low content of vinyl-1,2 unit (0.07). The mechanical properties in terms of tensile properties and abrasion resistance of the elastomer based on Ni/Nd-BR having high cis-1,4 and relatively higher trans-1,4 configurations were superior to elastomers based on commercial BRs produced by using Ni- and Nd-based catalyst systems. (C) 2015 Wiley Periodicals, Inc.