Bifunctional Carbanionic Synthesis of Fully Bio‐Based Triblock Structures Derived from β‐Farnesene and ll‐Dilactide: Thermoplastic Elastomers

Abstract

AbstractCurrent environmental challenges and the shrinking fossil‐fuel feedstock are important criteria for the next generation of polymer materials. In this context, we present a fully bio‐based material, which shows promise as a thermoplastic elastomer (TPE). Due to the use of β‐farnesene and L‐lactide as monomers, bio‐based feedstocks, namely sugar cane and corn, can be used. A bifunctional initiator for the carbanionic polymerization was employed, to permit an efficient synthesis of ABA‐type block structures. In addition, the “green” solvent MTBE (methyl tert‐butyl ether) was used for the anionic polymerisation, enabling excellent solubility of the bifunctional anionic initiator. This afforded low dispersity (Đ=1.07 to 1.10) and telechelic polyfarnesene macroinitiators. These were employed for lactide polymerization to obtain H‐shaped triblock copolymers. TEM and SAXS revealed clearly phase‐separated morphologies, and tensile tests demonstrated elastic mechanical properties. The materials featured two glass transition temperatures, at ‐ 66 °C and 51 °C as well as gyroid or cylindrical morphologies, resulting in soft elastic materials at room temperature.