Neodymium-Mediated Coordinative Chain Transfer Homopolymerization of Bio-Based Myrcene and Copolymerization With Butadiene and Isoprene

Coordinative chain transfer polymerization (CCTP) has emerged as a powerful strategy in controlling the polymerization behavior of petroleum-based diene monomers of butadiene (BD) and isoprene (Ip) and has been extensively studied in the past few years. Nevertheless, for the bio-based terpene monomer of myrcene (My), its polymerization performance is rarely disclosed. Herein, by using a neodymium-based Ziegler-Natta catalytic system of Nd(vers)3/Al(i-Bu)2H/AlEt3/EASC, the CCTP of My was systematically evaluated. In order to concrete the CCTP characteristic, more evidence was provided, including its comprehensive comparison with the Ip system, kinetic studies, and seeding polymerization. All these results have led to the conclusion that, despite the long alkenyl substitute in the My monomer, CCTP properties were still demonstrated, albeit with relative lower chain transfer efficiency. Coordinative chain transfer copolymerization (CCTcoP) of My with BD or Ip was also studied, in which, similar to My homopolymerization, well-controlled polymerization behaviors were also revealed that gave narrow polydispersities, high atom economies, as well as controlled copolymer compositions. Monomer reactivity ratio studies by Fineman-Ross plot revealed that, for CCTcoP of My and BD, rMy and rBD were determined as 0.62 and 0.27, whereas for My/Ip system, rMy and rIp values were 0.74 and 0.24, respectively, implying both two systems preferred to undergo cross-polymerization to give copolymers rather than homopolymer sequences.