Synthesis and characterization of high cis‐polymyrcene using neodymium‐based catalysts

The monomer β‐myrcene, a renewable resource, was polymerized in cyclohexane using two different Ziegler‐Natta catalyst systems based on neodymium Nd(Oi‐Pr)3 and NdV3. The Nd(Oi‐Pr)3 was combined with [HNMe2Ph][B(C6F5)4] (or [CPh3][B(C6F5)4]) and Al(i‐Bu)3 (or Al(i‐Bu)2H). Next, the NdV3 was activated using Al(i‐Bu)3 and AlEt2Cl. Both catalyst systems exhibited high polymer yields near 100 % in the established reaction time, high polymer molecular masses, and broad molecular mass distributions. The catalyst systems gave an effective and stereospecific polymerization reaction of β‐myrcene providing high cis selectivity of 1,4‐polymyrcenes (> 92 %) with a glass transition temperature between −66 and −62 °C. The above‐mentioned features of resulting elastomers in conjunction with the polymer's molecular masses and molecular mass distributions proved to be sensitive to borane and alkylaluminum compounds molar ratios, [B]/[Nd] and [Al]/[Nd] using Nd(Oi‐Pr)3 and [Cl]/[Nd] and [Al]/[Nd] with NdV3.