Using Redox-Switchable Polymerization Catalysis to Synthesize a Chemically Recyclable Thermoplastic Elastomer.
Using Redox-Switchable Polymerization Catalysis to Synthesize a Chemically Recyclable Thermoplastic Elastomer.
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DOI：
10.1002/anie.202317699
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发表时间：
2024-01
影响因子：
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通讯作者：
Jiangwei Liu;Sarah E. Blosch;Anastasia S Volokhova;Erin R. Crater;Connor F Gallin;Robert B Moore;John B. Matson;Jeffery A Byers
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文献类型：
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作者：
Jiangwei Liu;Sarah E. Blosch;Anastasia S Volokhova;Erin R. Crater;Connor F Gallin;Robert B Moore;John B. Matson;Jeffery A Byers
为了合成可化学回收的热塑性弹性体，开发了氧化还原可切换的催化体系以合成含有刚性聚（乳酸）（PLA）末端嵌段和柔性聚（四氢呋喃-共-氧化环己烯）（聚（THF-co-CHO）共聚物作为中间嵌段的三嵌段共聚物。通过改变铁基催化剂的氧化态诱导的正交反应性使得能够在单个反应烧瓶中由单体的混合物合成三嵌段共聚物。与聚（1-乳酸）（PLLA）相比，三嵌段共聚物表现出改善的柔韧性和类似于热塑性弹性体的热机械性能，包括在-60至40 °C范围内的橡胶平台。三嵌段共聚物含有较高百分比的THF相对于CHO是更灵活的，和三嵌段共聚物的共混物含有PLLA和聚（d-乳酸）（PDLA）的末端嵌段导致在立体复合物，进一步增加聚合物的灵活性。除了低成本的丙交酯和THF，这类新的三嵌段共聚物的可持续性也支持他们的解聚，这是通过暴露的共聚物顺序FeCl 3和ZnCl 2/PEG在反应蒸馏条件下。
In an effort to synthesize chemically recyclable thermoplastic elastomers, a redox-switchable catalytic system was developed to synthesize triblock copolymers containing stiff poly(lactic acid) (PLA) end blocks and a flexible poly(tetrahydrofuran-co-cyclohexene oxide) (poly(THF-co-CHO) copolymer as the mid-block. The orthogonal reactivity induced by changing the oxidation state of the iron-based catalyst enabled the synthesis of the triblock copolymers in a single reaction flask from a mixture of monomers. The triblock copolymers demonstrated improved flexibility compared to poly(l-lactic acid) (PLLA) and thermomechanical properties that resemble thermoplastic elastomers, including a rubbery plateau in the range of -60 to 40 °C. The triblock copolymers containing a higher percentage of THF versus CHO were more flexible, and a blend of triblock copolymers containing PLLA and poly(d-lactic acid) (PDLA) end-blocks resulted in a stereocomplex that further increased polymer flexibility. Besides the low cost of lactide and THF, the sustainability of this new class of triblock copolymers was also supported by their depolymerization, which was achieved by exposing the copolymers sequentially to FeCl3 and ZnCl2 /PEG under reactive distillation conditions.