Synthesis and characterization of high <i>cis</i>‐polymyrcene using neodymium‐based catalysts

Abstract

Abstract The monomer β ‐myrcene, a renewable resource, was polymerized in cyclohexane using two different Ziegler‐Natta catalyst systems based on neodymium Nd(O i‐ Pr) 3 and NdV 3 . The Nd(O i‐ Pr) 3 was combined with [HNMe 2 Ph][B(C 6 F 5 ) 4 ] (or [CPh 3 ][B(C 6 F 5 ) 4 ]) and Al( i ‐Bu) 3 (or Al( i ‐Bu) 2 H). Next, the NdV 3 was activated using Al( i ‐Bu) 3 and AlEt 2 Cl. 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 (&gt; 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(O i‐ Pr) 3 and [Cl]/[Nd] and [Al]/[Nd] with NdV 3 .