Polymerization of 1,3-butadiene using neodymium versatate: optimization of NdV 3 /TEAL/EASC molar ratios via response su
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Polymerization of 1,3‑butadiene using neodymium versatate: optimization of NdV3/TEAL/EASC molar ratios via response surface methodology (RSM) Ahmad‑ali Shokri1,2 · Saeid Talebi1,2 · Mehdi Salami‑Kalajahi1,2 Received: 15 May 2019 / Revised: 23 October 2019 / Accepted: 28 October 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract Response surface methodology (RSM) with central composite design was used to optimize and analyze the molar ratio of catalyst components for polymerization of 1,3-butadiene (Bd) using Ziegler–Natta catalyst. In this research work, the catalyst component includes neodymium versatate (NdV3) as catalyst, triethylaluminum as cocatalyst or activator and ethylaluminum sesquichloride as chloride donor. The symbols [Nd], [Al], [Cl] and [Bd] were used for catalyst, cocatalyst, donor and monomer concentration, respectively. The interaction between three important and critical variables was studied and modeled. For this purpose, independent variables are [Bd]/[Nd], [Al]/[Nd] and [Cl]/[Nd] molar ratios at three levels to optimize the dependent or response ones which are monomer conversion, molecular weight and cis content of resulting polymer. Quadratic models were achieved and developed to correlate the catalyst components’ molar ratio with dependent variables. The optimum conditions predicted via RSM were in good agreement with experimental data obtained from the experimental runs. The statistical analysis of the results showed that [Cl]/[Nd] molar ratio had a significant effect on monomer conversion and cis content. Furthermore, the catalyst components’ molar ratio to reach the desirable response parameters is forecasted and experimentally verified. The optimum catalyst components’ molar ratio derived via RSM is as follows: [Bd]/[Nd] = 5363.0, [Al]/ [Nd] = 27.2 and [Cl]/[Nd] = 2.2. Keywords Polymerization · Ziegler–Natta · Polybutadiene · Neodymium versatate · Response surface methodology * Saeid Talebi [email protected] * Mehdi Salami‑Kalajahi [email protected] 1
Department of Polymer Engineering, Sahand University of Technology, P.O. Box: 51335‑1996, Tabriz, Iran
2
Institute of Polymeric Materials, Sahand University of Technology, P.O. Box: 51335‑1996, Tabriz, Iran
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Polymer Bulletin
Introduction Polybutadiene rubber (PBR) is a resulting polymer of coordination polymerization of 1,3-butadiene (Bd) in the presence of Ziegler–Natta catalytic system. Among the annual global production of PBR, its largest portion is employed in the tire industries which are 70% of its production [1]. Neodymium (Nd)-based catalyst systems have shown considerable potential for Bd polymerization from the catalyst viewpoint [2]. Over half a century, Ziegler–Natta neodymium catalyst systems have been serviced for the synthesis of polydienes. One of the reasons for being of great interest is that unlike titanium catalyst systems, use of neodymium systems allows polymerization of diene monomers with high efficiency and stereospecificity and adjusts the characterist
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