Synthesis and Vulcanization of Polymyrcene and Polyfarnesene Bio-Based Rubbers: Influence of the Chemical Structure over the Vulcanization Process and Mechanical Properties

Abstract

The overuse of fossil-based resources to produce thermoplastic materials and rubbers is dramatically affecting the environment, reflected in its clearest way as global warming. As a way of reducing this, multiple efforts are being undertaken including the use of more sustainable alternatives, for instance, those of natural origin as the main feedstock alternative, therefore having a lower carbon footprint. Contributing to this goal, the synthesis of bio-based rubbers based on β-myrcene and trans-β-farnesene was addressed in this work. Polymyrcene (PM) and polyfarnesene (PF) were synthesized via coordination polymerization using a neodymium-based catalytic system, and their properties were compared to the conventional polybutadiene (PB) and polyisoprene (PI) also obtained via coordination polymerization. Moreover, different average molecular weights were also tested to elucidate the influence over the materials’ properties. The crosslinking of the rubbers was carried out via conventional and efficient vulcanization routes, comparing the final properties of the crosslinking network of bio-based PM and PF with the conventional fossil-based PB and PI. Though the mechanical properties of the crosslinked rubbers improved as a function of molecular weight, the chemical structure of PM and PF (with 2 and 3 unsaturated double bonds, respectively) produced a crosslinking network with lower mechanical properties than those obtained by PB and PI (with 1 unsaturated double bond). The current work contributes to the understanding of improvements (in terms of crosslinking parameters) that are required to produce competitive rubber with good sustainability/performance balance.

Conductive Conjugated Polymer Nanocapacitors for Localized Electrical Neurostimulation

“…NMR is a powerful tool for studying polymerization reactions. However, cross-linked polymers require a solid NMR technique due to their insolubility . To overcome the limitations that impose the insolubility of PEDOT or PPy polymers or EDOT-Py copolymers, we performed an in situ liquid NMR to monitor the progress of the reaction.…”

Polymerization of Bio‐Derived Conjugated Dienes with Rare‐Earth‐Metal Complexes

“…In addition to Far polymerization described above, [31,33,34] our research group [53] recently reported that the phosphine-functionalized fluorenyl ligated yttrium (39) catalytic system showed ultra-high activity (completely convert 500 equiv. of Far within 0.5 min) and perfectly 3,4-isoselectivity (3,4-= 100%, mmmm > 99%) for Far polymerization at room temperature (Figure 18).…”

“…Very recently, they [34] vulcanized PMyr and PFar manufactured by above catalytic system, and the different processes and mechanical properties of corresponding polymers were discussed. After sulfur vulcanization, due to crosslinking with branches, the tensile strengths of PMyr and PFar were decreased compared with those of polybutadiene and polyisoprene.…”

“…Later on, the same system was used to produce elastomeric nanocomposities, which were based on PMyr and polyfarnesene (PFar) and reinforced with alkylamine modified-graphene oxide. [33] Very recently, they [34] vulcanized PMyr and PFar manufactured by above catalytic system, and the different processes and mechanical properties of corresponding polymers were discussed. After sulfur vulcanization, due to crosslinking with branches, the tensile strengths of PMyr and PFar were decreased compared with those of polybutadiene and polyisoprene.…”

Bio‐based macroporous polymer sorbents: Synthesis, physicochemical properties and sorption kinetics

“…10 Due to its similarity to petroleum-based monomers and its widespread availability in nature, interest in synthesizing homo-and copolymers with different synthetic approaches, starting from β-myrcene, is increasing. Synthetic polymerization methods used for this purpose include ionic polymerization, [11][12][13][14][15] coordination polymerization, 16 controlled radical polymerization [17][18][19] and free radical polymerization. 20,21 The polymer microstructure and final properties of polymyrcenes are strongly dependent on the regioselectivity of the addition step and polymerization conditions (i.e., solvent, temperature, initiator).…”