Multifunctional poly(ethylene glycol) copolymers (mfPEGs) are accessible via the anionic copolymerization of functional epoxides with ethylene oxide (EO). Glycidyl ethers are conveniently synthesized from bio-renewable alcohols and epichlorohydrin (ECH). Herein, we present the synthesis of a series of acyclic terpenyl glycidyl ethers (TGEs) and their subsequent copolymerization with ethylene oxide (EO) via anionic ring-opening polymerization (AROP). The resulting library of copolymers with varied side chain length and comonomer composition comprises molar masses in the range of 4800 to 8300 g mol⁻¹ and narrow molar mass distributions (Đ = 1.06–1.13). For the copolymerization of the TGEs with EO, detailed ¹H NMR in situ kinetic studies revealed a change from ideally random to slight gradient copolyether microstructures with increasing chain length and hydrophobicity of the respective TGE. The living nature of AROP provides control of molar masses, and optimized reaction conditions, such as low reaction temperatures and a weakly bound cesium counterion, suppress the well-known proton abstraction of monosubstituted epoxides. Since the incorporation of the terpenyl side chains impedes crystallization, thermal properties of the copolyethers can be tailored by the monomer feed ratio. Subsequently, hydrogenation and thiol–ene click reactions at the side chain double bonds were carried out as post-polymerization modifications. The application of potassium azodicarboxylate (PADA) in the diimide reduction of the polymers was demonstrated to possess vast potential for the full hydrogenation of the novel copolymers, offering facile purification options. Overall, the copolymerization of EO and TGEs gives access to biobased, tailormade polyethers with various options for post-functionalization.

中文翻译：

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来自无环萜烯的缩水甘油醚：具有修饰机会的多功能聚乙二醇的多功能工具箱


多功能聚乙二醇共聚物 （mfPEG） 可通过官能环氧化物与环氧乙烷 （EO） 的阴离子共聚来实现。缩水甘油醚由生物可利用醇和环氧氯丙烷 （ECH） 方便地合成。在本文中，我们介绍了一系列无环萜烯基缩水甘油醚 （TGE） 的合成以及它们随后通过阴离子开环聚合 （AROP） 与环氧乙烷 （EO） 共聚。所得的具有不同侧链长度和共聚单体组成的共聚物库包括 4800 至 8300 g ^mol-1 范围内的摩尔质量范围和狭窄的摩尔质量分布 （Đ = 1.06–1.13）。对于 TGE 与 EO 的共聚反应，详细的 ¹H NMR 原位动力学研究表明，随着相应 TGE 的链长和疏水性的增加，共聚醚微观结构从理想随机变为轻微梯度。AROP 的活性特性提供了对摩尔质量的控制，而优化的反应条件（例如低反应温度和弱结合的铯反离子）抑制了众所周知的单取代环氧化物的质子提取。由于萜烯基侧链的掺入会阻碍结晶，因此可以通过单体进料比例来定制共聚醚的热性能。随后，侧链双键处的氢化和巯基-烯点击反应作为后聚合修饰进行。偶氮二羧酸钾 （PADA） 在聚合物二酰亚胺还原中的应用被证明具有新型共聚物完全氢化的巨大潜力，提供了简单的纯化选择。 总体而言，EO 和 TGE 的共聚提供了生物基、定制的聚醚，具有多种功能后化选项。