The synthesis of a fully biobased thermoplastic elastomer (TPE) is presented as an alternative to classical styrene/isoprene-derived TPEs. Limitations of classical systems, e.g., the microstructure of dienes or elaborate multistep addition pathways can be overcome by the combination of bifunctional initiation in the scarcely used, moderately polar solvent methyl tert-butyl ether (MTBE) and by using the monomers β-farnesene and nopadiene. The monomers can be derived from renewable sugar cane and pine tree feedstocks. Excellent control of carbanionic copolymerization is confirmed by in situ NMR kinetics. The study reveals that two-sided tapered ABA triblock copolymers are accessible in a one-step approach, capitalizing on a difunctional initiator in MTBE. The material properties can be tuned in a broad range─highly elastic materials with elongation exceeding 1300% as well as tough materials with Young’s modulus exceeding 500 MPa were obtained. Small-angle Χ-ray scattering, temperature-modulated differential scanning calorimetry, rheology, and dielectric spectroscopy were employed to relate the material properties to the phase state. They revealed local phase segregation accompanied by respective glass temperatures, albeit in the absence of long-range order.

中文翻译：

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全生物基双面锥形 ABA 型热塑性弹性体的一步合成


全生物基热塑性弹性体 (TPE) 的合成被提出作为经典苯乙烯/异戊二烯衍生的 TPE 的替代品。经典体系的局限性，例如二烯的微观结构或复杂的多步加成途径，可以通过在很少使用的中等极性溶剂甲基叔丁基醚（MTBE）中组合双功能引发并使用单体β-法呢烯和诺帕二烯。这些单体可以源自可再生的甘蔗和松树原料。原位核磁共振动力学证实了碳负离子共聚的良好控制。该研究表明，利用 MTBE 中的双官能引发剂，可以通过一步法制备双面递变 ABA 三嵌段共聚物。材料性能可在较宽范围内调节，获得伸长率超过1300%的高弹性材料以及杨氏模量超过500 MPa的坚韧材料。采用小角 X 射线散射、温度调制差示扫描量热法、流变学和介电谱将材料特性与相态联系起来。他们揭示了局部相分离伴随着各自的玻璃温度，尽管没有长程有序。