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

Abstract

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.

Anionic polymerization of dienes in ‘green’ solvents

“…1(c)). For the polymyrcenes, the T g values were in the range −71 to −48 °C, as expected, 19–21 and also linearly increasing with the vinyl content; however, the increase of T g was less steep than for the polyisoprenes. Generally, polymyrcenes exhibit a lower T g compared to polyisoprenes with the same microstructure.…”

“…Attractive renewable feedstocks are, among others, terpenes, especially monoterpenes (limonene or β‐myrcene) and also sesquiterpenes (β‐farnesene) 3–5 . Among these, β‐myrcene is a hydrocarbon 1,3‐conjugated diene, like butadiene, isoprene or β‐farnesene, which can be readily converted into a fully bio‐based elastomer by free‐radical, 6,7 controlled radical, 8,9 anionic, 10–17 cationic 18 or coordination polymerization techniques 19–21 . Polymyrcene with a high content of cis ‐1,4 units, resembling natural rubber ( cis ‐1,4‐polyisoprene), can be obtained by anionic or controlled radical polymerization, whereas highly trans ‐1,4‐ or isotactic 3,4‐polymyrcene is produced by coordination polymerization.…”

Stereoselective Copolymerization of Styrene with Terpenes Catalyzed by an Ansa-Lanthanidocene Catalyst: Access to New Syndiotactic Polystyrene-Based Materials

“…For instance, β-myrcene, or to a lesser extent β-farnesene, can polymerize via anionic or radical polymerization to form elastomeric materials [1]. In a few rare cases, the coordination (catalytic) polymerization of such monomers has been reported [2][3][4][5][6]. On the other hand, syndiotactic polystyrene (sPS) is a very attractive material due to its high melting point (ca.…”

Neodymium Catalyst for the Polymerization of Dienes and Polar Vinyl Monomers

“…However, the cis ‐1,4 stereoregularity was not reported in the publication . The study of ZN‐based lanthanide catalytic system for stereospecific polymerization of β‐myrcene is becoming more popular in the scientific community …”