POLYMERIZATION OF 1,3-BUTADIENE USING Co/Nd AND Ni/Nd CATALYSTS

Abstract

Commercial butadiene rubber (BR) synthesized from 1,3-butadiene (BD) polymerization using neodymium (Nd)-based Ziegler-Natta catalyst coordinated with alkylaluminium halides as co-catalysts contains 97-99 % cis-1,4 configuration, which is higher than BR produced from Ni- or Co- based catalyst system: Moreover, the Nd-based catalyst provides 100% BD conversion without gel formation in the obtained BR product and this system ฟสหน produces less vinyl-cyclohexene content. However, the BR obtained from Nd-based catalyst (Nd-BR) has high viscosity, which is inappropriate for the production of poly(acrylonitrile-butadiene-styrene) (ABS). The Nd-BR also has high cold flow properties inducing poor extrudibility. Since BR produced from Ni- (Ni-BR) and Co-based catalyst (Co-BR) has higher degree of branching, it results in better processability. However, Ni- and Co- based catalysts require triethylaluminum (TEAL) and diethylaluminum chloride (DEAC) as co-catalysts. Therefore, the objective of this research is to combine the advantage of these catalysts to produce BR with high content of cis-1,4 structure, good mechanical properties and easy processing. The results showed that the use of Nd mixed with Co (Co/Nd) and Nd mixed with Ni (Ni/Nd)- based catalyst systems coordinated with TEAL and DEAC in the presence of cyclohexane provided 90% and 100% BD conversion, respectively. The obtained BR had content of cis-1,4 configuration higher than 97% and low amount of vinyl-1,2 unit (0.14-0.40%) with the greater mechanical properties and abrasion resistance than the commercial BR produced by using Co- or Ni- based catalyst.