Terpene polymerization via a binary neodymium-based catalytic system with di-n-butylmagnesium as a co-catalyst

Abstract

The development of materials from renewable resources has been increasing, intending to reduce the consumption of fossil sources, with terpenes being one of the main families that reduce the consumption of isoprene. The study of the binary catalytic system neodymium versatate/dibutyl magnesium (NdV₃/Mg(n-Bu)₂), for the coordination homopolymerization of β-myrcene and β-farnesene, was carried out analysing different [Nd] : [Mg] ratios (between 4 and 10). Reporting conversions of 92% and 83% at an [Nd] : [Mg] ratio of 8 for polymyrcene (PMy) and polyfarnesene (PFa), respectively, and microstructures comprising 1,4 content above 80% for both polymers (PMy, cis-59% and PFa, cis-83%). It was observed that PFa samples presented a higher 1,4-cis content in relation to PMy samples, presumably due to the size of the side group present in the monomer structure and due to steric hindrance; similarly, a 3,4 content of 14% (PMy) and 10% (PFa) was observed. The glass transition temperature of the PMy samples ranged from −63.7 °C to −66.5 °C, while for the PFa samples, it was between −75.4 °C and −75.5 °C. The binary [Nd] : [Mg] system used in the study predominantly exhibited a 1,4-cis content at [Nd] : [Mg] ratios of 8.